Guides and instruments for improving accuracy of glenoid implant placement

ABSTRACT

A reaming guide is provided that includes a peripheral member configured to mate with a peripheral guide feature; a rigid body extending from the peripheral member to adjacent to a reaming head of a reamer, where the rigid body is configured to be mounted to the reamer proximal of the reaming head; and a depth stop coupled with the rigid body, the depth stop having a distal portion configured to contact a first reamed glenoid surface when the reaming head has fully reamed a second reamed surface to a planned depth, the second reamed surface being angled to the first reamed surface.

INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS

Any and all applications for which a foreign or domestic priority claimis identified in the Application Data Sheet as filed with the presentapplication are hereby incorporated by reference under 37 C.F.R. § 1.57.

BACKGROUND Field

The present disclosure relates to patient specific shoulder apparatusesand methods.

Description of the Related Art

Shoulder arthroplasty is an important solution to many shoulder jointailments. The procedure can involve replacing or repairing the articularsurface of one or both of the humerus and the glenoid to restoreshoulder joint function, to eliminate shoulder joint pain, and toimprove quality of life for patients with debilitating shoulder jointpain.

FIG. 1 illustrates a glenohumeral joint 8. An incision can be formed inthe tissue over the joint 8 to surgically expose a head 10 of thehumerus 12. The head 10 can be separated from the scapula 14 to provideaccess to the glenoid 18. FIG. 1A shows that retractors 16 can be usedto displace tissue surrounding the glenoid 18 to enhance access thereto.The retractors 16 help maintain an exposed surgical field during theprocedure.

In shoulder arthroplasty, an articular implant can repair or replace thearticular surface of the glenoid 18. The glenoid 18 is prepared by beingreamed a suitable amount and thereafter the articular implant isattached to the reamed surface. The articular surfaces of the humerus 12and the glenoid 18 can be reversed in some cases, providing a concavearticular member on the humerus 12 and a convex member on the glenoid18. In some cases the glenoid surface is worn away and the glenoidsurface is enhanced to make up for worn bone. In these cases poorarticular implant orientation can lead to poor results.

SUMMARY

There is a need for improved surgical guides that can improve placementof articular implants of the glenoid. There is a need for improvedsurgical guides that can aid in orienting glenoid articular implants.There is a need for improved surgical guides that can aid in formingchannels for screws and other anchors for glenoid articular implants.There is a need for surgical guides that have improved stability and forguides that can be placed on the glenoid without obstructing,interacting with and potentially being disrupted by or disrupting theposition or operation of tissue retractors and other surgical tools.There is a need for patient specific surgical guides that can provideany or all of these and other improved characteristics.

In one embodiment, a patient specific shoulder guide is provided thatincludes a hub and a plurality of peripheral members. The hub has afirst end configured to face a central glenoid surface, a second endopposite the first end, and an elongate hub body that extends from thefirst end to the second end. The elongate hub body defines a hub heightdimension that extends between the first end and the second end. Theperipheral members have an inner end coupled with the hub, an outer enddisposed radially away from the hub, and a patient specific contactsurface disposed at the outer end of the peripheral member. Each of theperipheral members has a peripheral member height dimension between thepatient specific contact surface and a side of the peripheral memberopposite the patient specific contact surface. At least one of theperipheral members is a low profile peripheral member in which theperipheral height dimension is less than the peripheral height dimensionof at least one other of the peripheral members or is less than the hubheight.

In another embodiment, a patient specific shoulder guide is provided.The patient specific shoulder guide includes a central member and aplurality of peripheral members. The central member is configured tocontact a location of a glenoid surface located inward of a glenoid rimof a glenoid. The peripheral members each have a patient specificsurface configured to contact points of the glenoid rim of the glenoidof a specific patient. The peripheral members and the central memberprovide for stable positioning of the patient specific shoulder guide.In use, all of the peripheral members contact an anterior portion of theglenoid rim. In this embodiment, there is optionally a side channel forsecuring the guide against rotation.

In another embodiment, a method is provided. A patient specific glenoidguide is placed on a surface of a scapula of a patient. The guide has apatient specific bone contact surface. The guide is placed such that thepatient specific bone contact surface is in contact with a correspondingbone surface. A peripheral guide pin is advanced into the scapula near aperipheral region of a glenoid of the patient with reference to thepatient specific glenoid guide.

In one variation of the foregoing method, an aperture of an anchortrajectory guide is advanced over the peripheral guide pin to apredefined position over the glenoid. A peripheral anchor channel isformed in the scapula from the glenoid surface toward an opposingcortical bone region. A reverse shoulder implant baseplate is secured onthe glenoid surface by advancing a peripheral anchor through theperipheral anchor channel formed through the anchor trajectory guide.

In another embodiment, a method is performed in which an anchortrajectory guide is positioned in a predefined position over a glenoidsurface of a patient. A peripheral anchor channel is formed in a scapulafrom the glenoid surface toward an opposing cortical bone region. Ashoulder implant is secured on the glenoid surface by advancing aperipheral anchor into the peripheral anchor channel formed through theanchor trajectory guide.

In one variation, a patient specific glenoid guide is placed on asurface of the scapula of a patient with the patient specific glenoidguide in contact with a corresponding bone surface. A peripheral guidepin is advanced into the scapula near a peripheral region of a glenoidof the patient with reference to the patient specific glenoid guide. Anaperture of the anchor trajectory guide is advanced over the peripheralguide pin.

The foregoing method can be employed to place a reverse shoulder implantbaseplate. The method can include coupling the reverse shoulder implantbaseplate to the anchor trajectory guide prior to positioning the anchortrajectory guide in the predefined position over the glenoid. Aprojection disposed on a bone facing side of the anchor trajectory guidecan be coupled with a recess in the reverse shoulder baseplate to couplethe reverse shoulder implant baseplate to the anchor trajectory guide.One or more peripheral members of the guide can be coupled with acorresponding one or more tooling interfaces of the reverse shoulderbaseplate to couple the reverse shoulder implant baseplate to the anchortrajectory guide.

In a further variation, the reverse shoulder baseplate can berotationally oriented such that an augmented portion thereof is orientedtoward a portion of the glenoid for which the augmented portion has beenconfigured.

The patient specific glenoid guide can be formed such that a centralguide feature is disposed to be near a central region of the glenoidwhen the guide is used. In one case, the central guide feature isestablished, at least in part by, advancing over a central guide pinextending from the central region of the glenoid.

In some methods, a reamer is advanced with reference to one or both ofthe central guide pin or the peripheral guide pin to the glenoidsurface. The glenoid surface is reamed with reference to the guidepin(s).

In another embodiment, a method of reaming a glenoid is provided. Apatient specific glenoid guide having a patient specific bone contactsurface is placed on a surface of a scapula of a patient. The guide isplaced such that the patient specific bone contact surface is in contactwith a corresponding bone surface. A central guide feature that extendsfrom a central surface of the glenoid is established. The central guidefeature is established by reference to the patient specific glenoidguide. A peripheral guide feature that extends from a surface of thescapula peripheral to the central surface of the glenoid is established.The peripheral guide feature is established by reference to the patientspecific glenoid guide. A reaming guide is coupled to a reamer. Aftercoupling the reaming guide to the reamer, the reaming guide is advancedover or into a proximal portion of the peripheral guide feature. Thereamer is advanced to the glenoid surface by reference to the centralguide feature and by reference to the peripheral guide feature. Theglenoid surface is reamed by continued reference to the central guidefeature and by reference to the peripheral guide feature.

In another embodiment, a patient specific shoulder guide is provided.The guide has a central hub, and a plurality of peripheral locatingmembers. The central hub has a channel therethrough. The channel ispositioned and oriented to define an axis along which a central guidepin can be placed in a glenoid of a patient. Each of the peripherallocating members is elongate with an inner end coupled with the centralhub and an outer end. The outer end is disposed away from the centralhub. A patient specific contact member is coupled with the outer end ofthe peripheral locating member. A peripheral member that has aperipheral channel therethrough is configured to direct a peripheralguide pin into a scapula adjacent to a rim of the glenoid outside thecentral region of the glenoid.

Any of the patient specific shoulder guides disclosed herein can includea surface configured to mate with a feature of a glenoid of a patient.

In some embodiments, one or more of the patient specific contact membersare formed as a substantial negative of corresponding portions of theglenoid of the patient. The peripheral member can have the peripheralchannel disposed in a portion of the shoulder guide configured to bedisposed over a superior portion of the glenoid when the patientspecific contact members are in contact with a surface of which they area substantial negative.

The peripheral member can have a peripheral channel configured to bespaced away from the scapula when the patient specific contact membersare in contact with a surface of which they are a substantial negative.The peripheral channel can have a trajectory that is patient specific.The peripheral channel(s) can be configured to direct a guide pin into aportion of the scapula outside the glenoid rim. The peripheralchannel(s) can be configured to direct a guide pin into a portion of thescapula inside the glenoid rim.

One or more of the peripheral members can be a low profile member inwhich a peripheral height dimension is less than a height of a centralhub. Two adjacent peripheral locating members can be disposed in aposterior portion of the shoulder guide and can be separated by anunobstructed region of at least 45 degrees, or of at least 90 degrees.The shoulder guide can be configured in a patient specific manner suchthat the peripheral channel will be disposed in a location outside of,e.g., opposite to, a region of the scapula to be reamed during aprocedure to place an implant on the glenoid.

In another embodiment, a reaming guide is provided that includes aperipheral member configured to mate with a peripheral guide feature anda rigid body. The rigid body extends from the peripheral member toadjacent to a reaming head of a reamer in use. The rigid body isconfigured to be mounted to the reamer proximal of the reaming head. Thereaming guide includes a depth stop coupled with the rigid body. Thedepth stop has a distal portion configured to contact a first reamedglenoid surface or other surface of the scapula when the reaming headhas fully reamed a glenoid surface to a planned depth in preparation foran augmented glenoid component. The reaming guide can be used to controlthe preparation of a surface that can be disposed at an angle to a firstreamed surface or that can be disposed at a non-orthogonal angle to aguide pin or at a non-orthogonal angle to a medial-lateral axis of thepatient.

In another embodiment, a patient-specific screw anchor trajectory guideis provided. The screw anchor trajectory guide includes a body, alocating aperture, and a plurality of peripheral screw apertures. Thebody is configured to be placed over a reverse shoulder assemblybaseplate. The locating aperture is disposed through the body and isconfigured to be advanced over a guide pin to locate the body relativeto a glenoid. The plurality of peripheral screw apertures are disposedthrough the body and located inferior of the locating aperture atpositions corresponding to pre-defined peripheral screw locations. Theperipheral screw channel apertures are located and oriented to providegood purchase in scapular bone around the glenoid for a specificpatient.

In some embodiments, a screw anchor trajectory guide can have a bodythat has a first side configured to face toward the glenoid surface inuse and a second side opposite the first side. The first side can have aprojection configured to be received in a recess of a glenoid baseplateto facilitate positioning the baseplate at the same time the screw guideis positioned to form peripheral screw channels.

One or more peripheral members can be provided on the first side of aguide body. The peripheral members can be configured to engage toolinginterfaces of a baseplate to facilitate positioning the baseplate at thesame time the screw guide is positioned to form peripheral screwchannels. The peripheral members can be disposed circumferentiallybetween adjacent holes of the plurality of peripheral screw apertures.The peripheral members can be disposed in an inferior portion and in asuperior portion of the body of the screw guide.

In some embodiments, a distance from a locating aperture of a guide to acentral portion of a medial projection of a body of the guide can beconfigured for a specific patient. One or more of the peripheral screwapertures can be configured for a specific patient. The peripheral screwapertures can comprise a superior hole, an inferior hole, an anteriorhole, and a posterior hole.

At least one of a plurality of peripheral screw apertures can bedisposed along an axis selected to cause a peripheral screw directedalong the axis to reach cortical bone through cancellous bone beneaththe glenoid.

At least two opposite peripheral screw apertures of a guide can bedisposed through a body of the guide along diverging axes.

In other embodiments, a surgical instrument is provided for implantingan augmented glenoid implant. The instrument includes an outer shell, aninner shell, and a rotation guide. The outer shell has an elongate bodythat has a first end and a second end. The outer shell has a glenoidimplant component retention feature disposed on the first end. The innershell is slideably disposed in the outer shell. The inner shell has afirst position and a second position within the outer shell. The firstposition is closer to the first end of the outer shell than is thesecond position. The inner shell is configured to actuate the glenoidimplant component retention feature to a retention configuration when inthe first position relative to the outer shell. The rotation guide hasan instrument interface and a bone interface portion disposed on anotherend thereof. The rotation guide has a rigid body disposed between theinstrument interface and the bone interface portion. The shape and/orlength of the rigid body optionally is/are configured for a specificpatient to control the rotational position of the glenoid implantcomponent. In some embodiment, the shape of the rigid body is configuredfor a specific patient to control the rotational position of the glenoidimplant component. In some embodiments the length of the rigid body isconfigured for a specific patient to control the rotational position ofthe glenoid implant component. In some embodiments the shape and thelength of the rigid body is configured for a specific patient to controlthe rotational position of the glenoid implant component. The surgicalinstrument comprises an interface portion configured to releasablyengage the rotation guide.

In some cases, the shape and/or length of the rigid body is/are notpatient specific but rather are generic. For example, a kit of rotationguides can be provided where each rigid body includes a generic body tosuit a small, a medium, or a large glenoid. The kit can further includefor each size option a plurality of rotation guides with rigid bodiesconfigured to align an instrument, such as a reamer or implant driver,with specific anatomy requiring augmentations, such as with posterior,inferior, anterior, or superior regions of the glenoid and any regiontherebetween.

In another embodiment a patient specific glenoid guide has a hub and aplurality of peripheral members. The hub has a first end configured toface a central glenoid surface, a second end opposite the first end, andan elongate hub body that is disposed between the first end and thesecond end. The elongate hub body has a central channel therethough. Theperipheral members have an inner end coupled with the hub, an outer enddisposed radially away from the hub, and a patient specific contactsurface at the outer end. At least one of the peripheral members has arotation control feature forming channel configured for forming a visualindicator on a scapula of a specific patient in a prescribed positionrelative to a portion of the glenoid of the specific patient to beaugmented by an augmented glenoid implant.

In another embodiment a method is provided for aligning a rotationallyasymmetric glenoid component to a glenoid of a specific patient. Theglenoid is exposed. A glenoid guide is applied to the glenoid. Theglenoid guide has a rotation control feature forming member. A rotationcontrol feature is formed with reference to the rotation control featureforming member in or on the scapula at or adjacent to the glenoid. Therotation control feature can be used for guiding a reamer to form asurface ready to receive a rotationally asymmetric glenoid component.The surface can be disposed at a non-orthogonal angle to a guide pin orto the orientation of a longitudinal axis of the reamer and/or at anacute angle to another reamed glenoid surface. Whether or not therotation control feature is used to control the reamer, the rotationallyasymmetric glenoid component can be advanced onto the glenoid withreference to the rotation control feature to align the rotationallyasymmetric glenoid component to the glenoid in a prescribed rotationalorientation for the specific patient. The rotationally asymmetricglenoid component is secured to the glenoid in the prescribed rotationalorientation for the specific patient.

The rotation control feature forming member can include a superiorperipheral member with an aperture and/or a guiding peripheral memberwith a channel. The rotation control feature can be configured to guideadvancement of a reamer to form a surface ready to receive arotationally asymmetric glenoid component. The surface can be disposedat a non-orthogonal angle to a guide pin or to the orientation of alongitudinal axis of the reamer and/or at an acute angle to anotherreamed glenoid surface. Whether or not the rotation control feature isused to control the reamer, the rotation control feature can beconfigured to guide placement of a rotationally asymmetric glenoidcomponent. The channel in the guiding peripheral member can be a slot orother open sided channel or can be a lumen or other closed peripherychannel.

Any feature, structure, or step disclosed herein can be replaced with orcombined with any other feature, structure, or step disclosed herein, oromitted. Further, for purposes of summarizing the disclosure, certainaspects, advantages, and features of the inventions have been describedherein. It is to be understood that not necessarily any or all suchadvantages are achieved in accordance with any particular embodiment ofthe inventions disclosed herein. No aspects of this disclosure areessential or indispensable.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects and advantages are described belowwith reference to the drawings, which are intended for illustrativepurposes and should in no way be interpreted as limiting the scope ofthe embodiments. Furthermore, various features of different disclosedembodiments can be combined to form additional embodiments, which arepart of this disclosure. In the drawings, like reference charactersdenote corresponding features consistently throughout similarembodiments. The following is a brief description of each of thedrawings.

FIG. 1 is a schematic view of a human shoulder joint showing the bonesthereof;

FIG. 1A is a schematic view of the glenoid surface of a scapula, accessto which has been enhanced by retractors;

FIG. 2 is an exploded view of one embodiment of a reverse shoulder jointglenoid implant that includes a baseplate;

FIG. 3 shows a perspective view of another embodiment of a baseplatethat can be used in the implant of FIG. 2 coupled with a glenoidsurface;

FIG. 4 shows a schematic representation of a baseplate similar to thatof FIG. 3 that is not properly placed on the glenoid surface, resultingin anchors that couple the baseplate to the scapula protruding from thescapula;

FIG. 5 shows the use of a patient specific glenoid guide in initialsteps of a shoulder surgery method for placing guide pins to guideplacement of anchors of a baseplate;

FIG. 5A is an enlarged view of the patient specific glenoid guide ofFIG. 5;

FIG. 6 shows methods of sizing a glenoid over a central guide pinextending away from a central region of a glenoid surface, the guide pinhaving been placed with reference to the patient specific glenoid guideof FIG. 5;

FIG. 7 shows methods of reaming with reference to the central guide pinshown in FIG. 6 which had been placed with reference to the patientspecific glenoid guide of FIG. 5;

FIG. 8 shows a method of advancing an anchor trajectory guide over aperipheral guide pin to a location adjacent to a glenoid surface, theanchor trajectory guide adapted to form a peripheral anchor channel inthe scapula, the peripheral guide pin placed using the patient specificglenoid guide of FIG. 5;

FIGS. 8A-8E show details of the anchor trajectory guide of FIG. 8, aloneand in combination with a baseplate, the anchor trajectory guide adaptedto form peripheral anchor channels in the scapula to assure goodpurchase in the bone for a specific patient;

FIG. 9 is a view similar to FIG. 4 showing the baseplate oriented suchthat each of peripheral anchors thereof find good purchase for aspecific patient;

FIG. 10 shows a reverse shoulder glenoid implant similar to that of FIG.3, where a baseplate thereof is augmented on a medial side thereof,

FIG. 10A shows a side view of the augmented baseplate of FIG. 10;

FIG. 11 shows a portion of a method of reaming a glenoid surface to forma complex reamed geometry thereon, the reamer having a depth stop andbeing advanceable over a central guide pin;

FIG. 12 illustrates further methods of reaming a glenoid surface byreference to a peripheral guide pin placed using the patient specificglenoid guide of FIG. 5;

FIG. 13 is a perspective bottom view of a reaming guide that can be usedto control reaming of a glenoid surface;

FIGS. 14-15 illustrate further methods of reaming a glenoid surface byreference to a peripheral guide peg assembly and a peripheral apertureformed using the patient specific glenoid guide of FIG. 5;

FIGS. 16A-16B illustrate components of the peg assembly of FIGS. 14-15in greater detail;

FIGS. 17-18 show a method involving advancing the baseplate of FIG. 10Ato and seating the baseplate on a glenoid surface that has been reamedaccording to one of the methods disclosed herein;

FIG. 18A shows an instrument the use thereof in a further method ofadvancing an augmented glenoid component such as the baseplate of FIG.10A to and seating component on a glenoid while providing control of therotational position of the component;

FIG. 18B shows a posterior side perspective view of a medial end of theinstrument of FIG. 18A coupled with a rotationally asymmetric glenoidcomponent;

FIGS. 18C and 18D show exploded views of certain portion of the surgicalinstrument illustrated in FIG. 18A;

FIG. 19 is a side view of a scapula showing potentially disruptiveinteraction between a retractor and a glenoid guide;

FIG. 20 shows a side perspective view of one embodiment of a low profileglenoid guide providing improved clearance for a tissue retractor;

FIG. 20A is a lateral or proximal side view of the glenoid guide of FIG.20;

FIG. 20B is a side view of the glenoid guide of FIG. 20;

FIG. 21 is a lateral side perspective view of another embodiment of alow profile glenoid guide placed on a scapula, the guide providingimproved clearance for a tissue retractor when so placed;

FIG. 21A is a medial or distal side view of the glenoid guide of FIG.21;

FIG. 21B is a side view of the glenoid guide of FIG. 21;

FIG. 22 is a medial or distal side view of another embodiment of a lowprofile glenoid guide providing improved clearance for a tissueretractor;

FIG. 22A is a side view of the glenoid guide of FIG. 22;

FIG. 23 is a lateral or proximal side perspective view of anotherembodiment of a low profile glenoid guide placed on a scapula, the guideproviding improved clearance for a tissue retractor;

FIG. 23A is a medial or distal side view of the glenoid guide of FIG.23;

FIG. 23B is a side view of the glenoid guide of FIG. 23;

FIG. 24 is a lateral side view of another embodiment of a low profileglenoid guide placed on a scapula, the guide providing improvedclearance for a tissue retractor;

FIG. 24A is a medial or distal side view of the glenoid guide of FIG.24;

FIG. 24B is a side view of the glenoid guide of FIG. 24;

FIG. 25A is a lateral or proximal side perspective view of anotherembodiment of a low profile glenoid guide providing improved clearancefor a tissue retractor;

FIG. 25B is a medial or distal side view of the glenoid guide of FIG.25A;

FIG. 26A shows a lateral or proximal side perspective view of anotherembodiment of a low profile glenoid guide placed on a scapula, the guideproviding improved clearance for a tissue retractor;

FIG. 26B is a medial or distal side view of the glenoid guide of FIG.26A;

FIG. 27A is a lateral side view of another embodiment of a patientspecific glenoid guide configured for forming a rotation controlfeature;

FIG. 27B is a medial perspective view of the patient specific glenoidguide of FIG. 27A;

FIGS. 27C-H illustrate various methods of aligning rotationallyasymmetric glenoid components using the patient specific glenoid guideof FIGS. 27A-27B;

FIG. 28A is a lateral side view of another embodiment of a patientspecific glenoid guide configured for forming a rotation controlfeature; and

FIG. 28B illustrates various methods of aligning rotationally asymmetricglenoid components using the patient specific glenoid guide of FIG. 28A.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

This application is directed to shoulder joint arthroplasty apparatusesand methods, which in some cases are patient specific. Section Idiscusses glenoid implants and the positioning of the same, addressingsome sub-optimal outcomes that can be improved by the surgical guidesdisclosed herein. Section II discusses methods and apparatuses forenhanced control of bone preparation for glenoid implants. Section IIalso discusses methods and apparatuses for enhanced control of themating of articular implant with the glenoid. Surgical guides arediscussed that enhance control of the rotational orientation of glenoidimplant components. Section III discusses methods and apparatuses forenhanced control of reaming of a glenoid surface. Reaming guides arediscussed that enhance the control of the process of reaming of aglenoid surface. Section IV discusses apparatuses and methods forproviding enhanced rotational position control during implantation ofrotationally asymmetric glenoid components, such as in certain augmentedglenoid components. Section V discusses low profile surgical guides forpreparation of the glenoid. Low profile glenoid guides are configured tobe less obstructive of other tools in the surgical field, such asretractors used to expose the joint space for procedures, and methods ofusing the same.

I. Glenoid Implant Positioning

Glenoid devices are implanted through an incision over the shoulderjoint. The incision is enlarged with one or more retractors 16. Theglenoid 18 is prepared through the enlarged incision to mate with animplant. Preferably the glenoid implant is oriented properly on theglenoid for a good joint replacement outcome. Patient specifictechniques can enhance glenoid implant positioning.

A. Example Glenoid Implants

FIG. 2 illustrates a reverse shoulder glenoid implant 50. FIGS. 10 and10A illustrate an augmented reverse shoulder implant 50A.

The glenoid implant 50 includes an anchor member 52 for anchoring theglenoid implant 50 in the glenoid, a baseplate 54, and a lockingstructure 56 that limits rotation between the anchor member 52 and thebaseplate. The implant 50 also includes a glenosphere 58 that has anarticular surface 59. The glenosphere 58 is couple to a concave humeralcomponent anchored to the humerus of the shoulder joint to provide jointmotion.

A longitudinal axis 60 is aligned with a central longitudinal axis 61 ofanchor member 52. The glenosphere 58 is disposed toward a proximal endof the glenoid implant 50 along the longitudinal axis 60 and the anchormember 52 is disposed toward the distal end of the glenoid implant 50along the axes 60, 61. An element of the glenoid implant 50 is proximalto another element if it is between the articular surface 59 and theother element and an element is distal to another element if it isbetween a distal tip 62 of the anchor member 52 and the other element.At some points below, reference may be made to the anatomical location.In use when the implant 50 coupled with a patient's scapula, the distaltip 62 is more medial on the patient, whereas the articular surface 59of the glenosphere 58 is more lateral on the patient.

The baseplate 54 is oriented substantially perpendicular to thelongitudinal axis 60 of the glenoid implant 50. The baseplate 54 has aproximal end 66 and a distal end 68. The proximal end 66 comprises aproximal surface and the distal end 68 comprises a distal surface, whichcan include a bone engaging surface 74. The bone engaging surface 74 isplanar in some applications. FIG. 10A shows that a bone engaging surface74A can comprise a more complex shape, such as a partial wedge shape insome applications. The bone engaging surface 74A can have a full wedgeshape or another complex shape.

The baseplate 54 has a peripheral surface 76 between the proximalsurface of the baseplate 54 and the bone engaging surface 74 of thebaseplate 54. In some embodiments, the peripheral surface 76 isconfigured to form a Morse taper with the glenosphere 58. Furtherdetails of such mating and other variations can be found inUS2015/0305877, which is hereby incorporated by reference in itsentirety.

The baseplate 54 has a central protrusion 78 that projects distally fromthe bone engaging surface 74 to the distal end 68. The centralprotrusion 78 has an outer surface that extends from the bone engagingsurface 74 to a distal end of the baseplate 54. The central protrusion78 can include a first aperture 80. The first aperture 80 can include agroove and a locking clip 83 to secure the anchor member 52 in thecentral protrusion 78. Further details of such securement andalternatives can be found in US2015/0305877, which is herebyincorporated by reference in its entirety. The baseplate 54, like thebaseplate 54A (shown in FIG. 3), can have a second aperture 82 thatextends from the first aperture 80 to the proximal end 66 of thebaseplate 54. The second aperture 82 can extend continuously from thefirst aperture 80 but may be smaller in diameter than the first aperture80.

The baseplate 54 and the baseplate 54A can include a plurality ofperipheral holes 84 (e.g., two holes 84 as in FIG. 2 or four holes 84 asin FIG. 3) positioned laterally of the second aperture 82. The holes 84are configured to accept peripheral anchors 86. The holes 84 extend fromthe proximal end 66 of the baseplate 54 to the bone engaging surface 74of the baseplate 54. Members 88 disposed within the holes 84 in thebaseplate 54 can be semi-spherical and can be surrounded by internalwalls of the holes 84. The internal members 88 can allow for advancementof the anchors 86 relative to the baseplates 54, 54A and can laterenlarge to create frictional connection therebetween preventing motion.The number and position of the holes 84 depends on many factorsincluding the anatomical structure of the patient, the diameter of theperipheral anchors 86, and size constraints dictated by dimensions ofthe baseplate 54 or the baseplate 54A.

In various embodiments discussed further below surgical guides andmethods using the same aid in aligning a wedge portion 394 of thebaseplate 54A with a bone segment in need of augmentation.

B. Example of Sub-Optimal Orientation of the Glenoid Implant

FIG. 4 shows a sub-optimal placement of the baseplate 54A and theperipheral anchors 86. The baseplate 54A and the glenoid 18 to which itis attached are asymmetric. The amount a location of the mass ofscapular bone to which the peripheral anchors 86 can be secured is notthe same beneath each of the holes 84 located in the periphery of thebaseplate 54A. Also, the baseplate 54A has an augmented portion thatshould be aligned with a portion of the glenoid 18 that is locally lowerthan other portions of the glenoid. FIG. 10A shows the augmented portionas a wedge portion 394 that extends partly across the bone engagingsurface 74. Improper orientation of the baseplate 54A leads to poorscrew engagement and gaps between the baseplate 54A and the glenoid 18.A sub-optimal orientation arises when a screw 86S disposed through ahole 84S that should be in a superior position on the glenoid 18 is infact placed at an inferior position. This error positions the wedgeportion 394 in the anterior position on the glenoid 18 when it is theposterior portion of the glenoid that would benefit from augmentation.This error causes an unacceptable gap between the glenoid 18 and anun-augmented portion of the bone engaging surface 74A. Also, theperipheral anchors 86 will not be seated well in the scapula 14. Anexcessive exposed distal length 90 of the anchor 86S extends out of thescapula 14 inferior to glenoid 18. An exposed length 92 of theperipheral anchor 86 in the superior position can be seen. The exposedlength 92 would be minimal to non-existent if the baseplate 54A wereproperly placed because the bone engaging surface 74A should conformclosely to the glenoid surface.

As discussed herein, improved surgical guides which can be patientspecific can be used to reduce, minimize or prevent these sub-optimaloutcomes in the implantation of the glenoid implant 50 and other glenoidimplants and components thereof such as the baseplate 54 and thebaseplate 54A.

II. Methods and Apparatuses for Enhanced Control of Bone Preparation andImplant Position

FIGS. 5-9 illustrate methods for enhancing control of the placement ofthe baseplates 54, 54A of the glenoid implant 50, 50A. These methods canemploy patient specific surgical guides to position peripheral guidepins and to form anchor channels in the glenoid

A. Guide for Forming Superior Peripheral Guide Channel

FIG. 5 illustrates steps of a shoulder surgery method following exposingof the glenoid 18. Once the glenoid 18 is exposed a patient specificshoulder guide 100 can be applied to, e.g., placed or secured to, asurface of the scapula 14. The patient specific shoulder guide 100 canbe placed in contact with a portion of the glenoid 18, such as theglenoid rim. The patient specific shoulder guide 100 can be placedadjacent to the glenoid rim. The patient specific shoulder guide 100 cancontact the glenoid rim and a portion of the scapula 14 outside theglenoid 18. The patient specific shoulder guide 100 can contact aportion of the scapula 14 outside the glenoid 18. The guide 100 can becoupled with the scapula 14 adjacent to the rim of the glenoid 18.

The guide 100 can be patient specific by having the gross dimensionsthereof (e.g., height in the inferior-superior direction, width in theanterior-posterior direction) matching the size of a glenoid of or otherportion of the scapula of a specific patient. The matching of theoverall size of the guide and the forming of specific portions thereofto match a specific patient result from a pre-planning process for theguide, which is followed by a manufacturing process to make a specificguide for a specific patient, as discussed further below. The guide 100can be patient specific in having one or more portions located centrallyand peripheral members or legs that extend radially outward from thecentral portion, the length, width, and/or separation between theperipheral members being patient specific. The peripheral members orlegs can also be patient specific in providing a contact portion forengaging in a patient specific manner a specific portion of the scapulaof a specific patient. For example, the peripheral members or legs canhave medial surfaces that are contoured to match, e.g., arecomplementary to or substantial negatives of, a segment of bone that canbe selected by a surgeon or that can be identified by a process asproviding optimal or enhanced fit for the guide 100. The contouredsurfaces can have, for example, simple or complex shaped concavitiesthat can be nested over similar or same shaped convexities of the bone,e.g., of the glenoid rim of the patient. When the contact surface orsurfaces is or are coupled with the anatomy to which they were formed tomatch the guide 100 can provide further functions. For example, thecentral portion if provided can be coupled with the peripheral membersor legs in a patient specific manner. For example, the central portioncan be coupled with the peripheral members such that it is at a patientspecific orientation or angle. The angle at which the central member iscoupled can enable a channel therethrough to be at a patient specificorientation to enable a pin to be guided into a central portion of theglenoid whereby the pin can guide other instruments at a pre-plannedpatient specific trajectory. The configuration of the hub, peripheralmembers, contact surfaces, pin guide orientation or trajectory and otherpatient specific features can be generated using a processor andcomputing system implementing a method that takes as inputs one or moreof pre-operative patient imaging, selection of bone portions to formcontact surfaces in relation to, nature and type of implant to beapplied to the patient following the surgery and other factors. Moredetails of acquisition of pre-operative images or data and processing ofthe same into plans for making and the patient specific shoulder guide100 are discussed in WO 2015071757 and WO 2015052586 which are herebyincorporated by reference herein.

Although the shoulder guide 100 generally is patient specific, it couldbe configured more generically in some embodiments. When patientspecific, the shoulder guide 100 can be formed following acquisition ofpre-operative imaging or data describing the actual bone anatomy of thepatient to be treated. CT or MRI scan images or the like can beobtained, digitized and analyzed using software. The software ispreferably combined with a manufacturing facility that allows thephysical structures of the patient specific shoulder guide 100 to bemade responsive to clinical judgements about the pre-operative images ordata. The manufacturing facility can employ or include additivemanufacturing such as three dimensional printing. Examples of threedimensional printing include direct metal laser sintering (DMLS), fuseddeposition modeling (FDM), fused filament fabrication (FFF), andelectron beam melting (EBM). Any one or a combination of these or otheradditive manufacturing processes can be used in to manufacture the guide100 or any of the other patient specific devices disclosed herein. Inthese processes a three dimensional object is formed by sequentiallyforming individual layers of the object on top of previously formedindividual layers. These processes can closely control the grossdimensions of the object and also can form complex features and shapessuch as contours. As discussed further below, these processes can beused to form and located the complementary surface on the guide suchthat the surface can mate with specific anatomy of a specific patient,e.g., concave surfaces that can nest on top of corresponding convexsurfaces. More details of techniques for manufacturing of the patientspecific shoulder guide 100 are discussed in WO 2015071757 and WO2015052586 which are hereby incorporated by reference herein.

FIGS. 5 and 5A show that patient specific shoulder guide 100 includes ahub 104 and a plurality of peripheral members 108. The patient specificshoulder guide 100 includes a posterior portion 112 and an anteriorportion 116. The posterior portion 112 and the anterior portion 116 ofthe guide 100 are configured to be positioned over posterior andanterior portions of the glenoid 18. The anterior portion 116 can have agreater number of peripheral members 108 than does the posterior portion112. In the illustrated embodiment, the anterior portion 116 includesthree peripheral members 108 and the posterior portion 112 includes oneperipheral member 108. The patient specific shoulder guide 100 also hasa peripheral member 108S in portion of the guide 100 configured to beoriented over a superior portion of the glenoid 18, hereafter thesuperior peripheral member 108S. The superior peripheral member 108S canbe located between the posterior portion 112 and the anterior portion116 of the guide 100. The spacing, size, and length of the peripheralmembers 108, 108S, 108P can be patient specific such that radially outerends thereof will extend to anatomy to which they are preplanned tocontact.

The hub 104 can have medial and lateral ends and a body that extendstherebetween. The medial end faces the glenoid 18 when the guide 100 ismounted to the scapula 14. The medial end can be disposed adjacent tobut may or may not contact the surface of the glenoid 18 when the guide100 is mounted to the scapula 14. The lateral end of the hub 104 islocated opposite the medial end of the hub 104. The lateral end of thehub 104 can be at the top side of the guide 100, e.g., an upper-mostportion or at least a local top portion of the guide 100.

The patient specific shoulder guide 100 can have a central channel thatextends through the hub 104. The central channel can extend from thelateral end to the medial end of the hub 104. The central channel of thehub first side 104 can be coupled with a pin guide 140 in someembodiments. In one embodiment, the central channel of the hub 104 has atapered profile, e.g., a profile that is circular in cross-section andthat has a larger diameter or circumference toward the lateral(proximal) end and a smaller diameter or circumference toward the medial(distal) end. The diameter or circumference can gradually butcontinuously decrease along a length between the lateral end and themedial end of the tapered profile. The diameter or circumference candecrease continuously from the lateral end toward the medial end of thetapered profile. The hub 104 can be formed or integrated into the guide100 by the manner in which the hub connects to the peripheral members108, 108S, 108P such that the orientation of the hub and the channeltherethrough are oriented to a direction selected by the surgeon or by aprocess that identifies an optimal or otherwise appropriate direction.

FIG. 5 shows that the pin guide 140 can include a tubular body 144. Thetubular body 144 can be cylindrical in form between proximal and distalends. In some embodiments, a distal portion thereof is tapered to matewith the central channel of the hub 104. For example, a length of thetubular body 144 disposed at or adjacent to a distal end thereof canhave a diameter or circumference that gradually but continuouslyincrease from at or adjacent to the distal end toward the proximal end.

FIG. 5A shows that in one embodiment, the peripheral members 108 in theanterior portion 116 can have an inner end 160, an outer end 164, and anelongate member 166 disposed therebetween. The inner end 160 can becoupled with the hub 104. The outer end 164 can be disposed opposite theinner end 160. The outer end 164 can be disposed radially away from theinner end 160. At or adjacent to the outer end 164, the peripheralmembers 108 can include a patient specific contact surface 168. Apatient specific contact member 172 can be disposed at the outer end 164of each of the peripheral members 108. The patient specific contactmember 172 can include a first end 176 and a second end 180. The firstend 176 can be coupled to the outer end 164 of the elongate member 166.The second end 180 can be a free end of the patient contact memberspecific 172. The second end 180 can include the patient specificcontact surface 168. The patient specific contact surface 168 isdisposed on the underside (or medial side) of the guide 100. The patientspecific contact surface 168 can be formed based on processing andanalysis of pre-operative images or data of the scapula 14 and/or theglenoid 18 and can be formed in a manufacturing process that is directedby such analysis, such as by additive manufacturing as discussed in moredetail above. FIG. 5A shows that one or more, e.g., all, of theperipheral members 108 in the anterior portion 116 can be configured tocontact the rim of the glenoid 18. The patient specific contact surface168 can have a shape that corresponds to, e.g., is complementary to andthat can be a negative of the natural contours of the glenoid 18including being shaped to mate to osteophyte or other natural bonystructures in a unique position or orientation.

FIG. 5A shows that one or more of the peripheral members 108 residing inthe posterior portion 112 can include one of the peripheral members 108that is configure to provide patient specific interaction in theposterior portion 112. The peripheral member 108 in the posteriorportion 112 can be similar to the peripheral members 108 in the anteriorportion 116 except as described differently below. The peripheralmembers 108 in the posterior portion 112 can advantageously beconfigured to reduce or minimize obstruction of the surgical field inthe posterior portion 112. For example, the peripheral member 108 of theposterior portion 112 can extend to a superior portion of the glenoidrim. A peripheral member 108P in the posterior portion 112 can beconfigured for patient specific mating in a region of the scapula 14located on, around, adjacent to, or even outside of the rim of theglenoid 18. This leaves a large uninterrupted portion of the rim of theglenoid 18 beneath the posterior portion 112 unobstructed. The elongatemember 166P can be longer than the elongate member 166 of the peripheralmembers 108 disposed in the anterior portion 116 of the patient specificshoulder guide 100 such that the peripheral member 108P can extend tothe superior portion Su of the glenoid rim. The posterior portion 112can be configured with a large unobstructed region 188. The unobstructedregion 188 can include an angle of 45 degrees or more. The unobstructedregion 188 can include an angle of 90 degrees or more. The unobstructedregion 188 can include an angle of 120 degrees or more. The unobstructedregion 188 can include an angle of 175 degrees or more.

Other approaches to making the patient specific shoulder guide 100 lowprofile in the posterior portion 112 are discussed below, includingmaking at least a portion of the peripheral members 108 in the posteriorportion 112, e.g., the elongate member 166P, with a lower height thanthe height of the peripheral members 108 in the anterior portion 116.FIGS. 20-26B show a number of other guides, the descriptions of whichare relevant to and can supplement the description of the guide 100. Forexample at least a portion of the guide 100, including one or all of theperipheral members 108 and/or the hub 104 can be low profile to allowfor improved access of other instruments in the surgical field.

The patient specific shoulder guide 100 includes a guide feature 192coupled with the hub 104. The guide feature 192 includes an inner endcoupled with the hub 104 an outer end disposed away from the inner endof the guide feature 192. The guide feature 192 includes an aperture 198disposed at or adjacent to the outer end thereof. The aperture 198 canbe used to secure the guide 100 against rotation, e.g., rotation aboutthe longitudinal axis through the hub 104, when the guide 100 is appliedto the patient. Other guides herein with peripheral apertures also canuse the peripheral apertures to secure such other guides againstrotation. The guide feature 192 can be configured as the peripheralmember 108S, e.g., can be located at a position of the patient specificshoulder guide 100 such that when the patient specific shoulder guide100 is properly placed on the scapula 14, e.g., on the glenoid 18 theaperture 198 is positioned at an appropriate position superior to theglenoid 18 to control aspects of methods that follow the stage depictedin FIG. 5. The peripheral member 108S need not be in direct contact withthe glenoid 18 and can be spaced apart from the glenoid when the guide100 is applied to the glenoid. The peripheral member 108S can in variousalternative embodiments have a portion in contact, e.g., in patientspecific contact, with the scapula 14. In one embodiment a lower portionof the peripheral member 108S is spaced from the scapula 14 when theguide 100 is mounted to the scapula. The aperture 198 can have atrajectory that is patient specific. For example, the aperture 198 canbe aligned to an axis therethrough that is perpendicular to a plane towhich the glenoid 18 is to be reamed. In some methods as discussedbelow, the glenoid 18 is reamed to a single plane. In some methods, theglenoid 18 is reamed in a manner having a more complex shape, e.g., withtwo, three, four or more than four portions that are not coplanar. Onemethod provides two planar regions on the glenoid 18 that meet at aboundary within the glenoid 18. The aperture 198 has a trajectory thatis perpendicular to one of these planes.

FIG. 5 shows that after the patient specific shoulder guide 100 has beenplaced and the pin guide 140 mated with the hub 104, a central guide pin204 and a peripheral guide pin 208 can be advanced into the scapula 14.The central guide pin 204 can be advanced as indicated by the arrow Ainto the tubular body 144. The central guide pin 204 can be directedinto the glenoid 18, e.g., into a central region of the articularsurface thereof. The peripheral guide pin 208 can be advanced asindicated by the arrow B through the aperture 198 of the peripheralmember 108S. The peripheral guide pin 208 can be directed into asuperior region of the glenoid 18, e.g., a portion of the articularsurface of the glenoid 18 just inward of the glenoid rim. In othermethods, the peripheral guide pin 208 can be directed into the glenoidrim. In other methods, the peripheral guide pin 208 can be directed intoa region of the scapula 14 outside the glenoid rim. The guide pin 208can be placed into any portion of the scapula 14 outside of the surfaceto be reamed, including generally superior of, generally anterior of,generally posterior of or generally inferior of a surface to be reamedor otherwise prepared in a subsequent step. As discussed in connectionwith the guide 1000 of FIG. 27A and with the guide 1050 of FIG. 28A, amark on the bone or the guide pin 208 in the bone can be placed througha channel 1010 in the guide 1000 or a channel 1060 in the guide 1050.The channel 1010, 1050 is disposed at a position relative to the portionof the glenoid to receive the most augmentation, e.g., 180 degreesoffset therefrom. The mark can provide for visual guidance ofinstruments, e.g., one or more of a reamer or an implant driver asdiscussed more fully below. The pin 208 can provide for direct slidingguidance of instruments, e.g., one or more of a reamer or an implantdriver as discussed more fully below. The central guide pin 204 and theperipheral guide pin 208 can be a conventional orthopedic guide pin suchas a Steinmann pin or a K-wire or similar structure. The central guidepin 204 may be longer than the peripheral guide pin 208 depending on theuse in relevant methods, some of which are discussed in detail below.The central guide pin 204 and the peripheral guide pin 208 are examplesof central and peripheral guide features that can be used in variousmethods herein.

The use of the superior peripheral member 108S to place the pin 208 canadvantageously be applied to other guides described herein, such as theguides of FIGS. 20-26B.

FIGS. 6, 7, and 12 show that other guide features can be used in othermethods as discussed herein. For example, the aperture 198 can be usedto direct the peripheral guide pin 208 into the scapula 14 to form aperipheral aperture 212 in the scapula 14. A drill, punch or otherchannel forming tool can be directed into the scapula 14 through theaperture 198 to form the peripheral aperture 212 in the scapula 14. Theperipheral aperture 212 can extend into the scapula 14 a sufficientdistance to receive in a later part of a various methods the peripheralguide pin 208, a peg or other guide member or reference device.

In one variation, one of the central guide pin 204 and the peripheralguide pin 208 is placed using the patient specific shoulder guide 100.The guide 100 can be used to form the peripheral aperture 212 or anotherguide feature but not to place the peripheral guide pin 208 initially.After the central guide pin 204 and/or the peripheral guide pin 208 areplaced or after the peripheral aperture 212 or a central aperture areformed or other reference provided in the glenoid 18 the patientspecific shoulder guide 100 can be removed from the glenoid 18 asindicated by the arrow C. The patient specific shoulder guide 100 andthe pin guide 140 can be removed together through the incision (notshown) which is provided in the tissue over the glenoid 18 to provideaccess to the glenoid as discussed above. The patient specific shoulderguide 100 and the pin guide 140 can be removed over the central guidepin 204 which may be sufficiently long to extend out of the proximal endof the tubular body 144 and out of the incision in some cases. Inanother method, the pin guide 140 is decoupled from the patient specificshoulder guide 100 and is removed first along the direction indicated bythe arrow C. After the pin guide 140 is removed, the patient specificshoulder guide 100 is removed along the direction indicated by the arrowC. If the peripheral aperture 212 is formed and a corresponding centralaperture is formed through the tubular body 144 or the hub 104 the pinguide 140 and the patient specific shoulder guide 100 can be removed inan unguided manner.

FIG. 6 shows a further step of determining the size of the glenoid 18after the central guide pin 204 has been inserted and the peripheralaperture 212 has been formed. A sizer 240 can be advanced along thecentral guide pin 204 in a direction indicated by the arrow D from aproximal end thereof (not shown) to adjacent to the glenoid 18. Thesizer 240 can include an outer periphery 244 that has a diameter thatmatches the anterior to posterior dimension of the glenoid 18. The sizercan have indicia 248 that correspond to a suitable size of the baseplate54 or the baseplate 54A. In another method, the peripheral guide pin 208is retained in the scapula 14. The patient specific shoulder guide 100is removed by sliding it proximally over the peripheral guide pin 208.The patient specific shoulder guide 100 can be removed by sliding itproximally over the central guide pin 204 and at the same time over theperipheral guide pin 208. FIG. 6 shows that the sizer 240 can beconfigured to be advanced over the central guide pin 204 withoutcontacting the peripheral guide pin 208. One approach to providing thiscapability is to configure the peripheral member 108S to extend adistance greater than the width of the glenoid 18 so that outerperiphery of the sizer 240 does not extend to the peripheral aperture212.

If the peripheral guide pin 208 is provided as illustrated in FIG. 5,the sizer 240 can be modified to be advanced over the peripheral guidepin 208 rather than over the central guide pin 204. For example, thesizer 240 can be generally circular as shown but can have a projection252 on one side that extends at least to the location of the peripheralaperture 212. The projection 252 can be positioned on a superior side ofthe sizer 240 if the sizer 240 is asymmetric other than the presence ofthe projection 252. The projection 252 can be positioned relative to theindicia 248 such that the indicia are upright when the projection 252 ison the peripheral guide pin 208 or mated with the peripheral aperture212. The projection 252 can be mated with the peripheral aperture 212 byproviding a peg or other projection disposed on a lower portion thereof.The use of a peg to mate with the peripheral aperture 212 is discussedbelow in connection with FIGS. 14-16B, which concept is fully applicableto the projection 252 of the sizer 240. By engaging the sizer 240 withthe guide pin 204 and with the aperture 212 or the pin 208 the sizer canbe aligned with a direction of the glenoid 18, such asanterior-posterior or inferior-superior.

Because the patient bony anatomy is characterized by CT or scan imagesor the like pre-operatively, using the sizer 240 to confirm the size theglenoid 18 and/or to pick an appropriate baseplate 54 or baseplate 54Ais optional or can be merely confirmatory. In some embodiments, the stepillustrated in FIG. 6 is not needed. If used, the sizer 240 isthereafter removed in a direction opposite the direction indicated bythe arrow D over the central guide pin 204 and/or over the peripheralguide pin 208.

FIG. 7 shows that before or after determining or confirming the size ofthe glenoid 18 or the appropriately size for the baseplate 54 or thebaseplate 54A the natural articular surface of the glenoid 18 can bemodified, e.g., can be reamed. In one method a cannulated reamer 270 isprovided. The cannulated reamer 270 has a channel therethrough that canbe inserted over the central guide pin 204. The cannulated reamer 270can be advanced over the central guide pin 204 to the surface of theglenoid 18. The cannulated reamer 270 can be rotated to move cuttingfeatures thereof over the glenoid 18. Further medially directed motiontoward or pressure on the glenoid 18 (e.g., in the direction indicatedby the arrow E) will result in a small amount of bone removal to providea controlled, e.g., planar surface. The reamer can take any suitableform but preferably includes a stationary outer sheath 274, a rotatablecutting head 278 and a lumen to receive the central guide pin 204. Aninternal drive shaft (not shown) coupled with the cutting head 278 canrotate within the outer sheath 274 to provide safe control cuttingaction at the cutting head 278 without harming other structures in thesurgical field. After the surface of the glenoid 18 has been prepared tomate with the baseplate 54, the reamer 270 can be removed from thecentral guide pin 204 in a direction opposite that of the arrow E.

As discussed below in connection with FIG. 11, the cannulated reamer 270can be exchanged for another reamer configured to create more complexgeometries at the surface of the glenoid 18. A rotation control devicecan be provided for reamers that are configured to ream a glenoidsurface asymmetrically, as discussed below in connection with FIGS.12-16B. Asymmetrical reaming can prepare the glenoid 18 for thebaseplate 54A as discussed further below.

B. User of Peripheral Guide Feature to Control Formation of PeripheralAnchor Channels

FIG. 8 shows a step of a method that can follow removal of thecannulated reamer 270 from the glenoid 18. The peripheral guide pin 208can be disposed in the peripheral aperture 212 in a superior location.In one method, reaming as in FIG. 7 is conducted without the peripheralguide pin 208 being present. For such a method, the peripheral guide pin208 can be placed after the reaming is complete. In other methods, theperipheral guide pin 208 is present during reaming and may be used tocontrol the position of the reamer 270 on the face of the glenoid 18.

The peripheral guide pin 208 is used to control the position of ananchor trajectory guide 290 in one embodiment. The anchor trajectoryguide 290 has an aperture 294 that can be advanced over the peripheralguide pin 208 along a medial direction, as indicated by the arrow F. Theaperture 294 can be disposed through a projection 298 of a body 302 ofthe anchor trajectory guide 290. The body 302 can have a first sideconfigured to face toward a glenoid surface in use and a second sideopposite the first side. The projection 298 of the anchor trajectoryguide 290 can comprise part of a superior portion 306 of the body 302 ofthe anchor trajectory guide 290. An inferior portion 310 of the body 302of the anchor trajectory guide 290 can include one or more, e.g., aplurality of, peripheral screw apertures 320.

FIGS. 8A-8C show further details of the anchor trajectory guide 290. Theanchor trajectory guide 290 can be patient specific, e.g., manufacturedfor a particular patient. As discussed, the bone around the glenoid 18is not symmetric and can be highly irregular. CT scan images or the likecan direct the manufacturing of some or all portions of the body 302 ofthe anchor trajectory guide 290 to a specific patient. In particular,based on a patient's shoulder anatomy and geometry, an anchor trajectoryguide 290 can be manufactured that is complementary to the patient'sspecific anatomy. The manufacturing of the anchor trajectory guide 290can be accomplished using additive manufacturing techniques to bespecifically configured to be complementary to the patient's specificanatomy. For example, a distance D1 from a central axis A5 of theaperture 294 to a central axis A6 of the aperture 82 of the baseplate 54or the baseplate 54A when coupled with the guide 290 can be configuredto suit a specific patient so that the distance from the peripheralaperture 212 to the entry point of a peripheral anchor 86 placed at thesuperior location will be as predetermined. Also, an angle α of acentral longitudinal axis A1 of the channel 324S to normal axis N1perpendicular to a medial or lateral side of the body 302 defines a bonechannel extending to the entry point on the glenoid 18 into the scapula14 and medially therefrom. A drill or punch following the channel 324Swill define a pathway that will provide a good outcome as discussedbelow in connection with FIG. 9. The channel 324S will be generally in amedial and superior direction (from the perspective of use when mountedas shown in FIG. 8). The medial end of the channel 324S will be medialand generally superior of the lateral end of the channel 324S.

Similarly the inferior peripheral screw aperture 3201 is positioned onthe body 302 of the anchor trajectory guide 290 to enable the inferiorperipheral screw aperture 3201 to direct a drill, a punch or similartool to form a channel in the glenoid 18. The inferior peripheral screwaperture 3201 can provide access to a channel 3241 disposed through thebody 302. The channel 3241 defines a central longitudinal axis A2 alongwhich the drill or punch can be directed. The central longitudinal axisA2 can be oriented in a patient specific manner, e.g. along an angle βrelative to the normal axis N2. The angle β is selected such that thetrajectory directed through the body 302 and through the baseplate 54Acauses the peripheral anchors 86 to reach cortical bone through thecancellous bone beneath the glenoid 18 but not to protrude therefrom orto protrude only a prescribed amount for a specific patient.

FIG. 8E shows further details of the anchor trajectory guide 290including patient specific configurations of peripheral screw apertures320. An anterior peripheral screw aperture 320A and a posteriorperipheral screw aperture 320P can be provided each of which can bepatient specific. The anterior peripheral screw aperture 320A can opento a channel 324A that is oriented at an angle γ relative to a normalaxis N3. The posterior peripheral screw aperture 320P can open to achannel 324P that is oriented at an angle δ relative to a normal axisN4. The angles γ and δ can be different from each other and can bepatient specific. The angle δ can be smaller than the angle γ. The angleδ is configured such that the axis A4 extends through the augmented partof the baseplate 54A. The angle γ can be configured such that a screwdirected along a central longitudinal axis A3 of the channel 324Aextends through the holes 84A of the baseplate 54A on a side oppositethe bone engaging surface 74A.

FIG. 8 shows that in one embodiment the anchor trajectory guide 290 cansupport the baseplate 54A in contact with the glenoid 18. FIGS. 8A and8C show more details of one embodiment for holding the baseplate 54A inplace on the anchor trajectory guide 290. FIG. 8A shows that the anchortrajectory guide 290 can include a central projection 328 disposed on adistal side 332 of the body 302. The distal side 332 is a first side ofthe body. The projection 328 is configured to be received in a recess ofa glenoid baseplate to facilitate positioning the baseplate at the sametime the screw guide is positioned to form peripheral screw channels.The central projection 328 can include an elongate body 336. In oneembodiment, the elongate body 336 is tapered between the distal side 332of the body 302 and a distal end 340 of the elongate body 336. Thetapered profile of the elongate body 336 provides one convenient mannerof coupling the anchor trajectory guide 290 with the baseplate 54A. Thedistal end 340 can be smaller in diameter than the second aperture 82.As such the second aperture 82 can be easily inserted over the elongatebody 336. The diameter of the elongate body 336 adjacent to the distalside 332 can be larger than the diameter of the second aperture 82. Inone approach an interference fit can be achieved between the anchortrajectory guide 290 and the baseplate 54A at a location along thelength of the elongate body 336. In one approach the anchor trajectoryguide 290 and the baseplate 54A is configured with a slip fit to theelongate body 336.

In addition, one or a plurality of peripheral members 344 can beprovided on the distal side 332 of the body 302. The members 344 areperipheral in that they are disposed in positions generally anterior andposterior to the protrusion 328, which is central compared to theposition of the members 344. The members 344 are circumferentiallybetween adjacent screw apertures 320 and in some cases are radiallyfarther from the projection 328 than are the apertures 320. The members344 can be offset in superior and inferior directions from each other.If an anterior-posterior line intersecting the projection 328 isprovided, one of the members can be seen to be disposed inferior to thisline and one can be seen to be disposed superior to this lien in oneembodiment. Each of the peripheral member(s) 344 can be configured to bereceived in a corresponding tooling interface 348 on the lateral side ofthe baseplate 54A. The engagement of the peripheral members 344 with thetooling interface 348 assures that the baseplate 54A and the anchortrajectory guide 290 can be coupled along a specific axis. The members344 facilitate positioning the baseplate 54A. The baseplate 54 isrotationally symmetrical so the baseplate 54 can be coupled in one oftwo rotational positions or at any rotational position. The baseplate54A is asymmetric in one embodiment where the wedge portion 394 isprovided. The baseplate 54A is oriented such that the wedge portion 394is aligned with a location of the glenoid 18 to be augmented. Thebaseplate 54A is then coupled with the anchor trajectory guide 290. Thebaseplate 54A and the anchor trajectory guide 290 can then be mounted tothe peripheral guide pin 208. In one patient wear pattern, the portionto be augmented is the posterior portion of the glenoid 18. Thebaseplate 54A is asymmetric so that the baseplate 54A is attached in theorientation in which the wedge portion 394 is aligned with a posteriorside of the anchor trajectory guide 290 (e.g., to the right as viewedfrom the lateral side for a left shoulder and to the left as viewed fromthe lateral side for a right shoulder).

In a different approach, the baseplate 54A is held in place on theglenoid 18 and the anchor trajectory guide 290 is aligned with thebaseplate 54A and then mounted thereto or separately supported.

A drill or punch can be directed through each one of the peripheralscrew apertures 320 and when so directed can also be direct through theholes 84A of the baseplate 54A. When so directed channels or pilot holesare formed in the scapula 14 from the reamed surface of the glenoid 18.The channels or pilot holes control the trajectory of the peripheralanchors 86 that are advanced through the holes 84.

FIG. 9 shows that the use of the anchor trajectory guide 290 improvesthe connection of the baseplate 54A to the scapula 14. In particular,the superior hole 84S with the peripheral anchor 86S disposedtherethrough is in the superior position of the glenoid 18 at oradjacent to the superior portion Su of the glenoid rim. The other threeperipheral anchors 86 are placed in the inferior, anterior, andposterior holes 84 of the baseplate 54A. In contrast with the outcomeshown in FIG. 4, the distal portions of each of the peripheral anchors86 and of the superior peripheral anchor 86S are embedded in bone andare not protruding through the bone by significant amounts. In pastpractice clinicians have been instructed to advance screws until theyprotrude from the scapula 14. This was done to assure that the tips ofthe screws were advanced into the cortical bone at the tip thereof. Witha patient specific approach, this practice is not needed. For example,any number or combination of patient specific configurations can makethe mounting of the baseplate 54A (or other baseplates discussed hereinor other glenoid implants) more accurate such that the surgeon can becertain of how the implant is seated. CT or MRI scan images and, asneeded, surgeon input can be processed to determine preoperatively howlong the peripheral anchors 86, the superior peripheral anchor 86S, orany combination of the screws 86, 86S should be. Also, if the anchors86, 86S are threaded, the thread pattern (e.g., pitch) can be madepatient specific. For example, the thread pattern (e.g., pitch) ofportions thereof will be lodged in cortical bone upon completion of theimplantation process can have a more suitable configuration for matingwith cortical bone and portions to mate with cancellous bone can have amore suitable configuration for mating therewith. The diameter of theanchors 86, 86S can be patient specific, such as providing largerdiameters for thicker and larger segments of bone of the specificpatient. The diameter of the anchors 86, 86S can be different atdifferent positions along the length thereof in a patient specificmanner, such that narrower sections will be provided in some areas thatwill mate with thinner or smaller bone sections and larger diametersections can be provided for areas that will mate with thicker andlarger segments of bone of the specific patient. Also, as discussedabove the anchor trajectory guide 290 can be formed in a patientspecific manner to assure that the trajectory of any or all of thescrews 86, 86S is/are predefined and accurate to the specific anatomy ofa specific patient. Any one or a combination or all of these patientspecific approaches including those defined by the anchor trajectoryguide 290 can enable the tips of the peripheral anchors 86 and thesuperior peripheral anchor 86S will be in pre-defined positions in thecortical bone of the scapula 14.

III. Enhanced Control of Glenoid Reamer

FIGS. 10 and 10A show further details of the glenoid implant 50A, whichnot only replaces the natural articular surface but also fills in someworn area of the glenoid 18. The implant 50A is similar to the glenoidimplant 50 except as described differently below. The glenoid implant50A includes the glenosphere 58, the anchor member 52 and the peripheralanchors 86. Although illustrated with two peripheral anchors 86, theglenoid implant 50A can be configured to have four peripheral anchors86. One of the peripheral anchors 86 extends through an augment portionconfigured to supplement the worn area.

The baseplate 54A has a proximal end 66 that is configured to bereceived in the glenosphere 58. A connection can be formed between aninternal surface of the glenosphere 58 and a peripheral surface of thebaseplate 54A just distal to the proximal end 66. The baseplate 54A hasa bone engaging surface 74A having a non-planar shape. In particular,the bone engaging surface 74A has a planar portion 390 that extends awayfrom approximately a mid-portion of the central protrusion 78 of thebaseplate 54A and a wedge portion 394 that extends away from the planarportion 390. The planar portion 390 can rest on a reamed surface of theglenoid 18 that has been reamed in a traditional manner. The wedgeportion 394 is configured to fill in a portion of the scapula 14 of thepatient. The portion filled in can be a portion that has been worn awayor can be just a relatively low area of the glenoid 18 that is desiredto be filled. The location and extent of the bone of the glenoid 18 tobe filled by the wedge portion 394 is determined via pre-operative CTscan, MRI images or the like. That information can be supplied to amanufacturing facility to custom make a patient specific baseplate 54A.Alternatively, the baseplate 54A can be in a kit with a range of sizes,shapes and angles of the wedge portion 394. A reaming process can beused to form a surface in the glenoid 18 to receive the wedge portion394.

FIG. 11 shows a step of a method that could follow the steps illustratedby FIG. 7. In FIG. 7 the cannulated reamer 270 is used to modify asurface of the glenoid 18. The cutting head 278 can be configured toform a generally planar surface S on the glenoid 18. After thecannulated reamer 270 has completed forming the glenoid 18, thecannulated reamer 270 can be removed along the central guide pin 204.FIG. 11 shows that thereafter an angle surface reamer 404 can beadvanced over the central guide pin 204. The angle surface reamer 404can include a cannulated handle 408 and a head 412 for reaming bone thatis rotated by a shaft within the cannulated handle 408. The anglesurface reamer 404 is advanced to ream a bone surface to form an angledsurface AS. The angled surface AS is at a non-zero angle to the planarsurface PS. Further advancement of the angle surface reamer 404 in adirection indicated by an arrow G after initial contact with the planarsurface PS transforms a portion thereof into the angled surface AS. Inone case, the angle surface reamer 404 includes a head 416 that limitsthe advancement along the central guide pin 204 in the direction of thearrow G. The angle of the head 416 to the cannulated handle 408 can beadjusted by the adjuster 420, for example to angles such as 15 degrees,25 degrees, and 35 degrees.

FIG. 12 shows an enhanced reaming assembly 430. The reaming assembly 430includes the angle surface reamer 404 and a reaming guide 432. Thereaming assembly reaming assembly 430 and the reaming guide 432 areexamples of rotational position control guides, sometimes referred toherein as rotation guides. The reaming assembly 430 and the reamingguide 432 can control unwanted rotation or other movement of the centerof rotation of the head 412 as the head 412 rotates. This helps preventthe head 412 from moving or walking or wandering across the glenoidwhich would result in imprecise reaming. The angle surface reamer 404has been discussed above. The reaming guide 432 includes a reamerinterface 460 and a rigid body 436 that extend from the interface 460.The reamer interface 460 engages a guide interface 462 that forms aportion of the angle surface reamer 404.

The reaming guide 432 is configured to be patient specific and toprovide advantages in preparing the glenoid of the specific patient. Forexample, as discussed further below the guide 432 is configure to matewith a specific side of the reamer 404, e.g., the side of the reameropposite the side toward which the head 412 can be oriented to providethe angled surface AS in the glenoid. The position of the angled surfaceAS can be different for each patient. In the illustrated treatment theangled surface AS will be on the posterior side of the glenoid. So, therigid body 436 is made patient specific in being configured such thatthe reaming guide 432 extends from a superior position coupled with thepin 202 to an anterior position for coupling with the reamer 404. Otherpatients may require the angled surface AS to be formed in an inferiorposition, so the rigid body 436 should be configured in a patientspecific manner to enable the reaming guide 432 to couple with the pin202 at a superior position and also with the reamer 404 in a superiorposition. Other patients may require the angled surface AS to be formedin an anterior position, so the rigid body 436 should be configured in apatient specific manner to enable the reaming guide 432 to couple withthe pin 202 at a superior position and to extent posteriorly to couplewith the reamer 404 in a posterior position. Other patients may requirethe angled surface AS to be formed in a superior position, so the rigidbody 436 should be configured in a patient specific manner to enable thereaming guide 432 to couple with the pin 202 at a superior position andto extend anteriorly or posteriorly around the reamer to couple with thereamer in an inferior position. In some cases, the reaming guide 432 ispatient specific in providing a depth stop for the reamer 404. Thus themedial-lateral length of a portion thereof can be configured for thespecific patient to define the extent of the reaming that is appropriatebased upon pre-operative imaging. Also, the medial end can include abone contacting surface that is patient specific, e.g., has acomplementary contour which can be concave to nest on or receives aconvex bone portion.

In one embodiment, the reaming guide 432 is configured to be removeablyattached to the angle surface reamer 404 by the reamer interface 460 andthe guide interface 462. The reamer interface 460 can include anactuator 480 that is moveable along the longitudinal axis of thecannulated handle 408. The actuator 480 can be retracted in thedirection of the arrow H. The guide interface 462 includes an axialmember or other mating structure on a distal end thereof that translateswith the cannulated handle 408. The angle surface reamer 404 can includea lateral peg 472 that is fixed thereon and is not moveable with theactuator 480. Retracting the actuator 480 moves the axial member ormating structure proximal of the lateral peg 472. The reaming guide 432can then be moved laterally such that a first aperture 464 thereofreceives the lateral peg 472. After the first aperture 464 is fullyreceived the actuator 480 can be released allowing the axial member ormating structure to move back into the second aperture 468 to secure thereaming guide 432 to the angle surface reamer 404. Movement of theactuator 480 to secure the reaming guide 432 to the angle surface reamer404 can be in the direction opposite to that illustrated by the arrow H.The movement can be upon action of a spring that is compressed when theactuator 480 moves in the direction of the arrow H. Further details ofthe guide interface 462 are discussed in US2015/0374502, which is herebyincorporated by reference herein in for this purpose and in itsentirety.

FIG. 13 shows that the rigid body 436 includes a projection 440 thatextends distally and proximally. The projection 440 includes a distalopening 444 and a proximal opening 448. An elongate body 452 extendsbetween the projection 440 and the distal opening 444. The elongate body452 preferably comprises a tubular member that encloses a guide lumen456 on all sides while the guide lumen 456 remains open on the ends. Theelongate body 452 is configured as a depth stop, e.g., having a lengththat is specific to the patient such that the free end (the medial end)thereof contacts the surface of the scapula 14 to prevent furtherreaming when the full planned extent of reaming has occurred.

FIG. 12 shows that after the reaming guide 432 is coupled to the anglesurface reamer 404, the rigid body 436 of the reaming guide 432 isdisposed medial of the head 412 of the angle surface reamer 404. Thereaming guide 432 does not obstruct motion of the head 412. The reamingassembly 430 can be moved over the central guide pin 204 and over theperipheral guide pin 208 in a guided manner. The distal opening 444 canbe advanced over a proximal end of the peripheral guide pin 208following advancement of the angle surface reamer 404 over the centralguide pin 204. After initially advancing the distal opening 444 over theperipheral guide pin 208 the elongate body 452 can surround theperipheral guide pin 208. The guide lumen 456 can be sized slightlylarger than the peripheral guide pin 208 such that there is little to nolateral movement as the reaming assembly 430 is further advanced in adistal direction along both the central guide pin 204 and the peripheralguide pin 208. Upon further distal motion the distal end of the elongatebody 452 makes contact with the scapula 14 adjacent to the periphery ofthe glenoid 18 at an intended depth. The proximal-distal position of thereaming assembly 430 over the central guide pin 204 and the peripheralguide pin 208 provided upon contact of the distal end of the elongatebody 452 is as shown in FIG. 12.

The advancement of the reaming guide 432 over the peripheral guide pin208 enables the angle surface reamer 404 to remain in a proper,prescribed rotational position over the central guide pin 204. Thisposition can assure that the head 412 acts as was intended based upon CTscan images or the like. As a result, the angled surface AS can be inthe position that was intended and the reamer 404 can be prevented fromoperating in other areas of the glenoid 18. By keeping the cannulatedhandle 408 in a proper rotational orientation relative to the centralguide pin 204 the location of the angled surface AS can be assured.

The rigid body 436 between the reamer interface 460 and the projection440 can be configured to locate the angled surface AS. In theillustrated embodiment, the rigid body 436 between the reamer interface460 and the projection 440 is curved to extend from a superior positionto locate the reamer interface 460 at an anterior position of theglenoid 18 when the guide lumen 456 is over the peripheral guide pin208. If it is desired to ream the angled surface AS in an inferiorposition, the rigid body 436 between the reamer interface 460 and theprojection 440 could be arranged to extend straight inferiorly to locatethe reamer interface 460 at a superior position when the guide lumen 456is over the peripheral guide pin 208. If it is desired to ream theangled surface AS in an anterior position, the rigid body 436 betweenthe reamer interface 460 and the projection 440 can be curved to extendfrom a superior position to locate the reamer interface 460 at aposterior position of the glenoid 18 when the guide lumen 456 is overthe peripheral guide pin 208. If it is desired to ream the angledsurface AS in a superior position, the rigid body 436 between the reamerinterface 460 and the projection 440 can be curved to extend from asuperior position anteriorly or posteriorly to locate the reamerinterface 460 at a position opposite the superior position, e.g., secondend 180 degrees from the superior position of the glenoid 18 when theguide lumen 456 is over the peripheral guide pin 208. The rigid body 436can have other patient specific configurations to locate the reamerinterface 460 at a position relative to, e.g., second end 180 degreesoffset from a location of the glenoid 18 to be reamed. Further to thediscussion above, the rigid body 436 can be patient specific in acircumferential extent, such that it is configured to extend about 90degrees counterclockwise from a superior position when applied. In oneembodiment the rigid body 436 is patient specific in a circumferentialextent, such that it is configured to extend about 180 degreescounterclockwise from a superior position when applied. In oneembodiment the rigid body 436 is patient specific in a circumferentialextent, such that it is configured to extend about 90 degrees clockwisefrom a superior position when applied. In one embodiment the rigid body436 is patient specific in extending radially from a first superiorposition to a second superior position, e.g., not extendingcircumferentially.

In on further variations discussed more fully below in connection withFIGS. 27A-28B the reamer 404 can be guided free-hand or over the guidepin 204 without requiring the guide pin 208. Rather the referencing theguide pin 208 the reamer 404 can be advanced free hand or over the guidepin 204 with reference another rotation control feature, such as a mark.The mark can be formed via a channel such as an enclosed channel 1010 oran open channel 1060. The mark so formed can provide visual guidance ofthe reamer 404 relative to the glenoid to properly orient the head 412to assure that the greatest extent of the reaming is at the properlocation of the glenoid as identified from pre-operative imaging.

FIGS. 14-16B show another embodiment of a reaming assembly 430A andvarious components thereof. The reaming assembly 430A includes the anglesurface reamer 404. The reaming assembly 430A also includes a reamingguide assembly 432A. As with the reaming assembly 430 and the reamingguide 432, the reaming guide assembly 432A is a rotation guide assemblyin that it guides the reamer 404 in controlling rotational position ofthe head 412 while uncontrolled movement of the rotational axis thereof.In one embodiment, the reaming guide assembly 432A includes a peg 490and a rigid body 498 that is engageable with the peg 490. The peg 490 isconfigured to mate with a peripheral aperture 212. The peg 490 caninclude a slender distal projection 494 that can be inserted into theperipheral aperture 212. The peg 490 can include a distal facingshoulder 505 configured to rest on the surface of the bone, e.g., in asuperior portion of the glenoid 18 when the distal projection 494 isdisposed in the peripheral aperture 212. The distal facing shoulder 505extends radially outward from the distal projection 494 to an enlargedbody 500. The distal facing shoulder 505 can be perpendicular to one orboth of the distal projection 494 and the body 500. In some embodimentsthe distal facing shoulder 505 can be a patient specific surface asdiscussed elsewhere herein, e.g., contoured to mate with the shape ofthe underlying bone. For example, the distal facing shoulder 505 canhave an annular surface extending radially away from the distalprojection 494. The annular surface can be patient specific, e.g.,having one or more contours in the axial or circumferential direction tonest over underlying bone. Such patient specific contours enable the peg490 to be placed in the peripheral aperture 212 in a specific rotationalposition such that a mating feature between the peg 490 and the rigidbody 498 is properly positioned. The enlarged body 500 is disposedproximally of the distal projection 494. The peg 490 can include aproximal portion 502 that extends proximally of the enlarged body 500. Aproximal facing shoulder 504 can be disposed between the enlarged body500 and the proximal portion 502. The rigid body 498 can mate with thepeg 490. In one embodiment, the rigid body 498 has a guide channel 506that can comprise a recess formed in the rigid body 498. The guidechannel 506 can comprise a lumen that extends entirely through theproximal-to-distal thickness of a free end of the rigid body 498. Theguide channel 506 is configured to receive a portion of the peg 490. Theguide channel 506 can be disposed in a superior portion 510 of the rigidbody 498. The guide channel 506 can be configured to mate with theproximal portion 502 of the peg 490. The proximal facing shoulder 504can mate with a distal side of the rigid body 498 when the peg 490 isfully received in the guide channel 506 of the rigid body 498. The peg490, in combination with the rigid body 498, is configured as a depthstop, e.g., having a length and a location of the proximal facingshoulder 504 that is specific to the patient such that the proximalfacing shoulder 504 mates with the distal side of the rigid body 498 toprevent further reaming when the full planned extent of reaming hasoccurred.

The reaming guide assembly 432A is advantageous in enabling a lower costapproach to providing patient specific reaming control. Cost is reducedbecause a portion of the reaming guide assembly 432A need not be patientspecific. That is, the rigid body 498 need not be patient specific solong as the peg 490 is patient specific. Only the peg 490 need be madefor a specific patient in some embodiments. In more detail, the peg 490can be configured in terms of length, surface geometry of patientcontact surface, size of contact surface, for example. The rigid body498 and the rest of the reaming assembly 430A can be universal and usedfor many different patients. To ensure that the reaming assembly 430Aoperates in a patient specific manner, in various embodiments a rotationcontrol interface 514 can be provided between the peg 490 and the rigidbody 498. The rotation control interface 514 can include a slot 518disposed on the superior portion 510. The slot 518 can extend from anoutside surface of the superior portion 510 to the guide channel 506.The slot 518 can be U-shaped as shown whereby a distal end thereof isopen. The open end of the slot 518 can be initially inserted over aproximal end of the peg 490 and advanced over the proximal portion 502until the slot 518 reaches the ridge 522. The ridge 522 can extendproximally from the enlarged body 500. In one embodiment, a steppedprofile is provided between the proximal portion 502 and the enlargedbody 500. The stepped profile can have a height (e.g., a change indiameter from the enlarged body 500 to the proximal portion 502) that isapproximately equal to the wall thickness of the superior portion 510 ofthe rigid body 498. The ridge 522 can have a length in the directionbetween the proximal and distal ends of the peg 490 that isapproximately the same as the length in the same direction as the slot518. The ridge 522 can be fully received in the slot 518 when the rigidbody 498 is placed over the proximal portion 502 of the peg 490. Whenthe ridge 522 is received in the slot 518 rotation between the rigidbody 498 and the peg 490 (and thus between the angle surface reamer 404and the bone) is limited, reduced or eliminated.

By at least limiting or reducing or in some cases by eliminatingrotation of the cannulated handle 408 while permitting rotation of thehead 412, the location of the angled surface that is reamed at an angleis more precisely controlled. FIGS. 17 and 18 show that a flat reamedsurface R1 and a posteriorly inclined surface R2 can be thus formed asprescribed. The flat reamed surface R1 can be generally perpendicular toa medial-lateral direction or plane of the patient. The angled reamedsurface R2 can be oriented relative to the flat reamed surface R1 in anamount and direction prescribed for the patient. Many patients sufferfrom erosion of the posterior portion of the glenoid 18. Such patientscan be treated more effectively using the angle surface reamer 404 andreaming guide 432. Other patients have erosion or degradation of bone inother zones of the glenoid 18. For such patient, the reaming guide 432or reaming guide assembly 432A can be modified to orient the head 412 toream the angled reamed surface R2 at the proper orientation, e.g., in ananterior portion, in an inferior portion, in a superior portion, or inother portions of the glenoid 18 such as posterior and inferior,posterior and superior, etc. The location to be reamed can be controlledby forming a portion of the reaming guide 432, 432A to be patientspecific as discussed above.

FIG. 17 shows that after the flat reamed surface R1 and the angledreamed surface R2 have been formed a driver 540 can be used to place thebaseplate 54A on the glenoid 18. The driver 540 can include an outershell 544 with a distal end configured to mate with the baseplate 54A.The driver 540 can also include an inner shaft 548 configured to matewith the anchor member 52. The inner shaft 548 can rotate within theouter shell 544 so that the baseplate 54A can be held stationary whilethe anchor member 52 is rotated by the inner shaft 548. The wedgeportion 394 can be aligned with the angled reamed surface R2 as thebaseplate 54A is held without rotation by the outer shell 544. The innershaft 548 can rotate the anchor member 52 to advance the anchor member52 and the baseplate 54A toward the bone until the planar portion 390contacts the flat reamed surface R1 and the wedge portion 394 contactsthe angled reamed surface R2 as shown in FIG. 18.

FIGS. 17 and 18 are inferior side views of the scapula 14 and theglenoid 18. Although not shown, the peripheral guide pin 208 or a peg,such as the peg 490 can be placed in the peripheral aperture 212 at oradjacent to the superior side of the glenoid 18 to control, minimize oreliminate rotation of the outer shell 544 away from a prescribedorientation such that the alignment of the wedge portion 394 is to theangled reamed surface R2 as prescribed.

IV. Enhanced Rotational Position Control of Glenoid Component

While the driver 540 can provide for adequate placement and control ofcertain implants, it may be advantageous in certain instances to moreprecisely control one or more components. Examples of components thatcould benefit from more precise control include rotationally asymmetriccomponents that perform most optimally when aligned to an intendedrotational position. The baseplate 54A is one such component in that thethicker wedge portion 394 is intended to be placed at the angled reamedsurface R2 which is a surface that has been prepared for such placement.FIGS. 18A-18C show certain patient specific instruments and assembliesthat can improve angular position control with reference to an apertureformed in the scapula in a surgical method step. FIGS. 27A-28B showmethods of using a glenoid guide to form a rotation control feature,e.g., a mark on or a channel or pin in the bone as a visual referencefor subsequent steps of advancing and securing the baseplate 54A orother rotationally asymmetric implant component.

A. Surgical Instrument for Enhanced Position Control of Glenoid Implant

FIG. 18A shows a surgical instrument 550 that is well suited forimplanting the baseplate 54A or another augmented glenoid implant orcomponent. The surgical instrument 550 includes an outer shell 544. Theouter shell 544 includes an elongate body 552 that has a first end 554and a second end 556. The outer shell 544 has a glenoid implantcomponent retention feature 558. The glenoid implant component retentionfeature 558 can be disposed at the first end 554. The glenoid implantcomponent retention feature 558 is adapted to securely couple with aglenoid component, such as the baseplate 54 or the baseplate 54A.

In one embodiment, the glenoid implant component retention feature 558with one or more tines 558A located on each of two peripheral members558B for engaging a tooling interface 348 of the baseplate 54A. Theperipheral members are able to flex such that the tines 558A can bemoved away from and toward a longitudinal axis of the elongate body 552.The peripheral members can each comprise a semi-circular arc 558C. Eachof the tines 558A can be disposed in the approximate center of one ofthe arcs 558C. The ends of one of the arcs 558C can face but be spacedapart by gaps from the ends of the other arcs 558C. The gaps 558Cbetween the ends of the arcs allow the arcs to move away from each otherand toward each other.

FIG. 18B shows an enlarged view of a medial end of the surgicalinstrument 550. This view shows the screw 577 and the baseplate 54Acoupled with the elongate body 552 of the outer shell 544. Also, therotation guide 561 is coupled with the outer shell 544 of the surgicalinstrument 550. The rigid body 498 of the rotation guide 561 is coupledwith the peg 490.

FIG. 18C shows that the surgical instrument 550 can also include aninterface portion 559 that is adapted to interface with, e.g., toreleasably engage a rotation guide 561 as described further below. FIG.18D shows that the interface portion 559 can include a spring-loadedball 559A or other detent structure to engage an aperture 464A or otherrecess in the rotation guide 561 such that secure but releasableconnection can be made between the outer shell 544 and the rotationguide 561. The aperture 464A and the first aperture 464 can becontiguous with one another. In some variations the rotation guide 561is integrated into and is not removeable from other components of thesurgical instrument 550, such as the outer shell 544.

An inner shell 560 is disposed within the outer shell 544. In certainembodiments the inner shell 560 is configured to slide within the outershell 544. For example, the outer shell 544 can have a lumen that islarger than an outer periphery of the inner shell 560 at least along alength thereof adjacent to the second end 556. This allows a first end570 of the inner shell 560 to be inserted into the second end 556 of theelongate body 552. The first end 570 can then slide toward the first end554 of the elongate body 552. The lumen of the elongate body 552 can besmaller than an outer periphery of the inner shell 560 at least adjacentto the first end 570 of the inner shell 560. Further advancement of theinner shell 560 within the lumen of the outer shell 544 can result inretention of the baseplate 54A or other component to be placed.

In certain embodiments, the inner shell 560 can have a first positionand a second position within the outer shell 544. The first position canbe somewhat retracted from the first end 554 such that the tines 558A ofthe glenoid implant component retention feature 558 can be allowed todeflect or can be located toward the longitudinal axis of the elongatebody 552. The second position can be one in which the first end 570 ofthe inner shell 560 is advanced relative to the first end 554 of theouter shell 544 such that the first end 570 is located within theglenoid implant component retention features 558. In some embodiments,the second position is one in which the first end 570 is within oradjacent to a portion of the glenoid implant component retention feature558 which causes the tines 558A to expand into a retention configurationwith the baseplate 54A.

Certain embodiments are configured for maintaining the retentionconfiguration without continued surgeon manipulation of the surgicalinstrument 550. For example, a threaded interface can include threads575 disposed on an elongate body of the inner shell 560. The firstposition of the inner shell 560 can be provided by sliding orlongitudinal translation, e.g., without requiring rotation. The secondposition can be achieved by engaging through rotation the threads 575with corresponding threads in the lumen 576 of the elongate body 552.The threaded interface can enhance the force applied to the glenoidimplant component retention feature 558 to provide greater security ofthe baseplate 54A (or other component) to the surgical instrument 550.Rotation of the inner shell 560 can be enhanced by a knob disposed atthe second end 572 thereof. Upon complete rotation of the inner shell560 the first end 570 is fully disposed in and fully actuates theglenoid implant component retention feature 558 to provide secureretention. The threaded interface also has sufficient friction againstcounter-rotation that the position of the inner shell 560 within theouter shell 544 can be maintained even after the surgeon releases theinner shell 560.

The surgical instrument 550 can include a rotation guide 561 configuredto provide increased control of the surgical instrument 550 and therebyof a rotationally asymmetric glenoid implant, such as the baseplate 54A.The rotation guide 561 can have the same configuration as the reamingguide assembly 432A but of course is incorporated into the surgicalinstrument 550. The rotation guide 561 can include a rigid body 498. Therigidity of the rigid body 498 prevents the surgical instrument 550 frommoving out of an intended position, as discussed further below. Therotation guide 561 can include an instrument interface, such as thefirst aperture 464 and/or the aperture 559B, and a bone interfaceportion. The first aperture 464 (or other instrument interface) is usedto connect the rotation guide 561 with another part of the surgicalinstrument 550. The connection of the rotation guide 561 to another partof the surgical instrument 550 can be temporary. The instrumentinterface can engage the interface portion 559. In certain embodimentsthe interface portion 559 is the same as or similar to the lateral peg472, discussed in connection with FIGS. 12 and 14 above. The lateral peg472 can have the spring-loaded ball 559 a disposed therein. The lateralpeg 472 can be disposed on the surgical instrument 550, e.g., disposedon the outer shell 544 of the surgical instrument 550. The rotationguide 561 can interface with the bone with a separable structure such asthe peg 490, which is discussed above. As discussed, the peg 490 canhave a patient specific contact surface, e.g., at the distal facingshoulder 505. The bone interface portion of the rotation guide 561 caninclude the guide channel 506 of the rigid body 498.

FIG. 18C shows that the instrument and bone interfaces can be located onopposite ends of the rigid body 498. The configuration of the rigid body498 between the instrument and bone interfaces controls the rotationalposition of the surgical instrument 550 and thereby the baseplate 54A orother rotationally asymmetric component coupled therewith as thebaseplate or component is being coupled with the prepared glenoid. Insome embodiments, the shape of the rigid body 498 is configured for aspecific patient to control the rotational position of a glenoid implantcomponent. In some embodiments the length of the rigid body 498 isconfigured for a specific patient to control the rotational position ofa glenoid implant component. In some embodiments the shape and thelength of the rigid body 498 is configured for a specific patient tocontrol the rotational position of a glenoid implant component. In aspecific example, the guide channel 506 is configured to be advancedover a peg 490 that is placed in the peripheral aperture 212 disposed ata superior glenoid position. In one case, the shape and length of therigid body 498 result in the first aperture 464 being positioned at theanterior side of the glenoid generally in a mid-region along asuperior-to-interior axis. This position allows a thicker part of thebaseplate 54A (e.g., the wedge portion 394) to be aligned to a moreextensively reamed or otherwise more medial portion of the glenoid. Asdiscussed elsewhere herein the shape and/or length of the rigid body 498can result in placement of the thicker part of the baseplate 54A to bein any pre-defined position, which position can be patient specificbased on pre-operative imaging (e.g., CT scan, MRI scan, X-ray or thelike) and analysis as discussed herein.

The interface portion 559, e.g., the lateral peg 472, can be configuredto releasable engage the outer shell 544 with the rotation guide 561.This configuration enables the rotation guide 561 to be used only onetime and to enable the rest of the surgical instrument 550 to be cleanedand used again with another patient.

In one embodiment, the interface portion 559 is disposed on a sideopposite to where the wedge portion 394 of the baseplate 54A is to bepositioned when properly aligned to and coupled with the glenoid implantcomponent retention feature 558. As a result, the surgeon knows withoutany visual confirmation that the baseplate 54A is properly aligned whenthe interface portion 559 is coupled with the rigid body 498 at theinstrument interface, e.g., at the first aperture 464 and the guidechannel 506 is coupled with the peg 490 placed in the peripheralaperture 212. The bone interface portion of the rotation guide 561,e.g., the guide channel 506, could be placed over the peg 490 which isplaced inferiorly. The rigid body 498 could then extend anteriorly andsuperiorly to an anterior position to align the wedge portion 394 withthe angled reamed surface R2 if that surface is located in the posteriorportion of the glenoid. The bone interface portion, e.g., the guidechannel 506 could be placed over the peg 490 when placed in theperipheral aperture 212 at a superior position. The rigid body 498 ofthe rotation guide 561 could then extend anteriorly and inferiorly to ananterior position to align the wedge portion 394 with the angled reamedsurface R2 if that surface is located in the posterior portion of theglenoid. Many other variations can be employed to place the wedgeportion 394 in any angular position around the glenoid, e.g., inferior,anterior, superior, posterior, or any location between these angularpositions.

Although the rotation guide 561 is illustrated as an assembly of the peg490 and the rigid body 498, the rotation guide 561 could be configuredsimilar to or the same as the reaming guide 432 in which the elongatebody 452 is adapted to be advanced over a guidewire until the distalopening 444 is abutting the surface of the glenoid. In such embodimentsthe wire can be considered a portion of the rotation guide 561. Theelongate body 452 can include a patient specific medial face forcontacting the patient. The length of the elongate body 452 can be suchthat the glenoid 18 when the medial face contacts the glenoid. The rigidbody 436 extends to the first aperture 464 which can engage theinterface portion 559 (e.g., receive the spring loaded ball 559 a of thelateral peg 472 in the aperture 464A).

FIG. 18C shows how the surgical instrument 550 is assembled. The innershaft 548 can be coupled with the inner shell 560 by inserting the firstend 564 (of 566) into the second end 572 of the inner shell 560. Theinner shaft 548 can slide within the lumen 574 until at least the torqueinterface 562 emerges from the first end 570. In this position the knobat the second end 572 is adjacent to the medial end of the handle 566 ofthe inner shaft 548. The inner shell 560 together with the inner shaft548 can be inserted into the first end 570 of the outer shell 544.Specifically, the torque interface 562 and the first end 570 can beinserted into the second end 556 and advanced within the lumen 576 untilat least the torque interface 562 emerges from the second end 556. Inthis position the knob of the inner shell 560 is between the handle 566and the second end 556 of the outer shell 544. The rotation guide 561can also be coupled with the interface portion 559 of the surgicalinstrument 550. As discussed above, in one embodiment the interfaceportion 559 is on the outside surface of the elongate body 552 of theouter shell 544. Thus, the interface portion 559 can be coupled to theouter shell 544. The baseplate 54A can then be coupled with the glenoidimplant component retention feature 558. For example, the tines 558A canbe inserted into the tooling interface 348 of the baseplate 54A. Afterbeing so inserted, the first end 570 of the inner shell 560 can be movedtoward the first end 554 of the outer shell 544. This movement is to asecond position, which is one in which the baseplate 54A is securelyheld to the surgical instrument 550. Such secure holding or retentioncan be achieved by engaging the threads 575 with internal threads inlumen 576 of the outer shell 544.

The inner shaft 548 can freely rotate within the lumen 574 when theinner shell 560 is in the first position and when the inner shell 560 isin the second position within the outer shell 544. As a result, thebaseplate 54A can be held stationary on the glenoid implant componentretention feature 558 while the inner shaft 548 rotates. The surgeon canhold the knob at the second end 572 of the inner shell 560 whilerotating the handle 566 at the first end 564 of the inner shaft 548. Inone embodiment, the inner shaft 548 is solid with no lumens. Thetrajectory of advancement of a screw 577 (see FIG. 18A) coupled with thetorque interface 562 can be controlled either by pre-forming a centralchannel in the glenoid 18 or by the rigidity of the rotation guide 561or a combination of these structures. In other embodiments, the innershaft 548 is cannulated with a lumen for tracking over a guidewire.

Having described the structure of the surgical instrument 550, thefollowing provides examples of how the surgical instrument 550 can beused. After the glenoid 18 is exposed, a peripheral aperture 212 can beformed in the scapula 14, e.g., at a superior position of the glenoid18. The peripheral aperture 212 is one example of a rotation controlfeature as discussed herein. The peripheral aperture 212 can be placedanywhere around the glenoid 18 in variations of the method. Theperipheral aperture 212 can be formed using a glenoid guide, such as thepatient specific shoulder guide 100. For example, a drill or punch canbe directed through the aperture 198 in the peripheral member 108S.

A rotationally asymmetric glenoid component, such as the baseplate 54A,can be advanced onto the glenoid 18. The advancement of the baseplate54A can be with reference to the peripheral aperture 212 or to anotherrotation control feature. Such advancement can align the rotationallyasymmetric glenoid component to the glenoid 18 in a prescribedrotational position for the specific patient. The reference to theperipheral aperture 212 can be in any suitable manner. FIG. 18A showsthat in one example, the peg 490 and the rotation guide 561 are used toreference the peripheral aperture 212. The peg 490 and the rotationguide 561 are shown assembled together and the rotation guide 561assembled to the outer shell 544 of the surgical instrument 550. Thearrows in FIG. 18C show how this assembly can occur. That is the innershaft 548 can be inserted into the inner shell 560. The inner shaft 548and the inner shell 560 can thereafter be inserted into the outer shell544. The first aperture 464 of the rotation guide 561 can then beadvanced over the interface portion 559, which can be configured in amanner similar to the lateral peg 472.

FIG. 18A shows that as the screw 577 is initially advanced into acentral region of the glenoid 18. As discussed above, the rotation ofthe screw 577 can be achieved by rotating the handle 566 relative to theinner shell 560 and/or the outer shell 544. The surgeon can grasp andhold stationary the knob at the second end 572 of the inner shell 560while rotating the handle 566 to provide this relative rotation. Thescrew 577 can be advanced into a pre-formed central aperture, which canbe formed by the patient specific shoulder guide 100 or by any otherguide disclosed herein. Rotation of the screw 577 causes the threadsthereof to advance the screw 577 into the glenoid 18 and the rest of thesurgical instrument 550 toward the glenoid 18. Further advancementbrings the distal projection 494 of the peg 490 into the peripheralaperture 212. The peripheral aperture 212 thereafter prevents anyrotational movement of the elongate body 552 and therefor the glenoidimplant component retention feature 558 and the baseplate 54A by itsinteraction with the distal projection 494 of the peg 490. Theperipheral aperture 212 and the peg 490 therefor assist in maintainingthe alignment of the baseplate 54A to the glenoid 18 in a prescribedrotational orientation for the specific patient.

Further rotation of the screw 577 draws the baseplate 54A intoengagement with the lateral surface of the glenoid 18. The amount ofadvancement of the screw 577 can be patient specific. For example, thedistal facing shoulder 505 of the peg 490 can be patient specific inmating with the glenoid 18 in a specific manner. The medial-lateraldistance from the glenoid 18 to the interface portion 559 can determinefor the specific patient how far the screw 577 is advanced. For example,the position of the rigid body 498 from the distal end of the innershell 560 can determine how close the torque interface 562 is to theglenoid 18 when the distal facing shoulder 505 contacts the scapula 14preventing further medial motion of the surgical instrument 550.

In one variation, part of advancing the baseplate 54A onto the glenoid18 includes coupling a rigid body 436 with the baseplate 54A and withthe peripheral aperture 212. This can be done by first mating the peg490 with the peripheral aperture 212. Thereafter the screw 577 isadvanced until the guide channel 506 is disposed adjacent to theproximal portion 502 of the peg 490. The guide channel 506 can beconfigured as a lumen in a cylindrical member and can be formed to slideover the proximal portion 502. Further advancement of the screw 577causes the guide channel 506 to be advanced over the proximal portion502 until the slot 518 mates with the ridge 522 that projects laterallyof the proximal facing shoulder 504 of the peg 490. The peg 490 providesa direct bone interface portion. The guide channel 506 provides anindirect bone interface portion, e.g., through the peg 490.

In one variation, a peripheral wire is used in place of the peg 490. Theguide 432 can mate with the outer shell 544 of the surgical instrument550 and can slide over the wire. The guide 432 can be configured tocontact the glenoid 18 of the specific patient when the screw 577 hasbeen advanced an amount prescribed prior to the surgery. The guide 432can be non-specific as to the depth of the screw 577 but be patientspecific in other ways. For example, the guide 432 can be shaped orsized to couple with the interface portion 559 to retain the surgicalinstrument 550 and thereby the baseplate 54A in a prescribed rotationalposition relative to the glenoid 18 of the specific patient.

Once the screw 577 is fully advanced, additional peripheral screws canbe placed. Prior to placing the peripheral screws the surgicalinstrument 550 is disengaged from the lateral side of the baseplate 54A.This can be achieved by retracting the inner shell 560 such that thefirst end 570 is spaced further away from the glenoid implant componentretention feature 558 allowing the tines 558A to slip out of the toolinginterface 348 of the baseplate 54A. Thereafter peripheral screws can beadvanced through the peripheral holes 84 in the baseplate 54A. Theplacement of the peripheral screws can be made patient specific by anysuitable method, such as any of the patient specific methods describedherein. For example, the anchor trajectory guide 290 can be mated withthe baseplate 54A to direct a punch or drill to form the peripheralscrew apertures in a patient specific manner.

B. Surgical Instrument for Enhanced Position Control of Glenoid Implant

While a surgical instrument with a patient specific rotation guide canbe used to advance and secure an implant to the glenoid withoutrequiring direct visualization of the scapula, FIGS. 27A-28B illustratevarious apparatuses and methods that benefit from facilitating bonemarkings to control rotational position of a rotationally asymmetricglenoid component. FIGS. 27A-28B illustrate various devices that canprovide a visible rotation control features, such as a mark. The markcan be used to guide a reamer to form a surface ready to receive arotationally asymmetric glenoid component. The surface can be disposedat a non-orthogonal angle to a guide pin or to the orientation of alongitudinal axis of the reamer and/or at an acute angle to anotherreamed glenoid surface. Whether or not the rotation control feature isused to control the reamer, the mark or other rotation control featurecan be used to control angular orientation of a rotationally asymmetricimplant, such as the baseplate 54A. An advantage of the devices of FIGS.27A-27B is that rotational position control can be provided in ashoulder guide that serves other purposes, e.g., to form a central orperipheral aperture for placement of pins therein to guide reaming,peripheral screw channel formation or other patient specific or genericmethods.

FIG. 27A shows a glenoid guide 1000 that can be used to provide a mark1014 on the scapula 14, e.g., on the glenoid rim 17 or the glenoid 18.The shoulder guide 1000 can have similar structures to any of the otherglenoid guides described herein. The description of all of the otherguides is therefore incorporated by reference here and will not bereiterated but should be considered to supplement the followingdiscussion of the glenoid guide 1000.

The glenoid guide 1000 includes a posterior portion 1002 and an anteriorportion 1004. The glenoid guide 1000 is configured such that whencoupled with the glenoid 18 of a specific patient, the posterior portion1002 is disposed over the posterior portion of the glenoid 18 and theanterior portion 1004 is disposed over the anterior portion of theglenoid. The glenoid guide 1000 includes a hub 104 that is disposed in acentral region of the glenoid guide 1000, e.g., where the posteriorportion 1002 and the anterior portion 1004 come together. Althoughgenerally centrally located, the hub 104 can be off-set from thegeometric center of the glenoid 18 depending on the specific patientneeds. The location of the hub 104 should correspond to the location ofthe geometric center of the baseplate 54 or the baseplate 54A to beplaced on the glenoid 18. The location of the hub 104 and a centralchannel therethrough can be shifted superiorly of the geometric centerof the glenoid 18 for a specific patient. The location of the hub 104and a central channel therethrough can be shifted inferiorly of thegeometric center of the glenoid 18 for a specific patient. The locationof the hub 104 and a central channel therethrough can be shiftedanteriorly of the geometric center of the glenoid 18 for a specificpatient. The location of the hub 104 and a central channel therethroughcan be shifted posteriorly of the geometric center of the glenoid 18 fora specific patient. The glenoid guide 1000 includes a plurality ofperipheral members 108. The posterior portion 1002 includes oneperipheral members 108 and the anterior portion 1004 includes threeperipheral members 108. Each of the peripheral members 108 includes aninner end 160 coupled with the hub 104 and an outer end 164 disposedradially away from the hub 104.

The glenoid guide 1000 has height in a medial-lateral direction. FIG.27B shows this dimension in connection with the hub 104, which has afirst end 120, a second end 124, and an elongate body 125 disposedbetween the first end 120 and the second end 124. The first end 120faces the glenoid 18 when applied thereto, and therefore is on themedial side of the glenoid guide 1000. The second end 124 faces awayfrom the glenoid 18 and thus is on the lateral side of the glenoid guide1000. Each of the peripheral members 108 can also have one or moreheight dimensions. The span between the inner end 160 and the outer end164 can have a height dimension less than that of the hub 104. Theradially outer portion of each of the peripheral members 108 can have apatient specific contact surface 168, as discussed in connection withthe patient specific shoulder guide 100. The medial-lateral dimension orheight of one or more of the peripheral members 108 can be less thanthat of one or more of the other peripheral members 108 as discussedmore in connection with FIGS. 19-26B.

The glenoid guide 1000 can be configured with a central channel 136 anda channel 1010 that is located peripherally. The central channel 136extends through the hub 104. The peripheral channel 1010 extends throughthe outer end 164 of one of the peripheral members 108. Morespecifically, the glenoid guide 1000 includes a peripheral member 108Rhaving an enlarged radially outer end with a patient specific contactsurface 168 on the medial side thereof. The peripheral channel 1010extends through the enlarged outer end from the lateral side to themedial side of the glenoid guide 1000. The central channel 136 isconfigured for forming a channel and or placing a central guide pin 204as discussed above. The peripheral channel 1010 is configured forforming a rotation control feature, e.g., a visual indicator on thescapula 14 of a specific patient in a prescribed position. Theprescribed position is with reference to a portion of the glenoid 18 ofthe specific patient to be augmented by an augmented glenoid implant,such as the baseplate 54A. For example, the position can be at anangular position spaced away from a portion of the glenoid of thespecific patient to be augmented. The position can be opposite, e.g.,180 degrees offset from, a position of the glenoid to be augmented by anaugmented implant. In one embodiment the peripheral member 108R islocated on the anterior portion 1004 of the glenoid guide 1000. Theperipheral member 108R can be located in other parts of the glenoidguide 1000, e.g., in the posterior portion 1002 or in an inferior orsuperior portion, or at any positions between these locations. Theangular position can be based on the imaging data and analysis, e.g.,upon a study of one or more CT scans, MRI scans, X-rays or the like.

FIG. 27A shows that the configuration of the peripheral channel 1010 cancomprise an enclosed periphery 1012 that surrounds the peripheralchannel 1010 on all sides. The enclosed periphery 1012 provide forprecise guiding of a marking instrument, which is not shown but can besimilar to a bovie pen. In other techniques, a marking instrument caninclude a drill bit or a surgical pin. The enclosed periphery 1012results in a small symmetrical mark that can be used in guiding aninserter as discussed below. As discussed further below, the peripheralchannel 1010 can be used to form a mark 1014 in an anterior (or other)portion of the glenoid 18 that is spaced away from (e.g., opposite to) aposterior (or other) portion of the glenoid 18 to be augmented using arotationally asymmetric glenoid implant, such as the baseplate 54A. Insome embodiments, the peripheral channel 1010 is 180 degrees off-setform the location of the glenoid to receive the greatest augmentation.In some embodiments, the peripheral channel 1010 is located at adifferent off-set position that is amenable to visual confirmation, suchas 90 degrees and superior to or 90 degrees and inferior to the locationof the glenoid to receive the greatest augmentation. In the glenoidguide 1000 the peripheral channel 1010 is disposed in a peripheralmember 108 such that the mark 1014 is made directly on the glenoid rim17 of the specific patient. For example, the medial end of theperipheral channel 1010 can be located on a portion of the patientspecific contact surface 168 of the peripheral member 108R.

FIGS. 27C-27H illustrate methods of using the glenoid guide 1000. FIG.27C shows relevant anatomy in a schematic form. The glenoid 18 isdisposed in a lateral region of the scapula 14. The glenoid rim 17defines a boundary that surrounds a central region of the glenoid 18.The anatomy shown schematically in FIG. 27C can be visualized after theglenoid 18 has been surgically exposed. The glenoid guide 1000 ispatient specific, as discussed above, such that when the glenoid guide1000 is applied to the glenoid 18 the peripheral members 108 are placedon the scapula 14, the glenoid 18, and in the method illustrated in FIG.27D directly on the glenoid rim 17 in a preferred, optimal location.Application of the glenoid guide 1000 in this location can arise fromforming the patient specific contact surface 168 based on imaging dataof the specific patient, as discussed elsewhere herein. One of theperipheral members 108 is disposed on the posterior portion 1002 of theglenoid 18. Two peripheral members 108 and the peripheral member 108Rare disposed on the anterior portion 1004.

FIG. 27E shows a portion of a method involving forming a rotationcontrol feature, in the form of a mark 2014, on the scapula 14, e.g., onor straddling the glenoid rim 17. The mark can be applied by a bovie pen1015 which is illustrated schematically. In other techniques, the markcan be applied or made using a drill bit or a surgical pin. Also, acentral mark, aperture or the central guide pin 204 can be placed usingthe central channel 136 as discussed above in connection with thepatient specific shoulder guide 100.

FIG. 27F shows that after the mark 1014 is made and the mark, apertureor central guide pin 204 is made or placed, the glenoid guide 1000 canbe removed from the area of the glenoid 18. FIG. 27G shows thatthereafter the baseplate 54A or another rotationally asymmetric implantcan be delivered and secured to the glenoid 18. Although any suitableinstrument can be used, the driver 540 is shown schematically with thebaseplate 54A shown in dashed line. The baseplate 54A can be coupled tothe driver 540 in any suitable manner, such as similar to theinteraction between the outer shell 544 and the inner shell 560 toactuate the glenoid implant component retention feature 558 into aretention configuration. If the driver 540 is cannulated, the innershaft 548 can be advanced over the central guide pin 204 which can beplaced through the glenoid guide 1000. The driver 540 can include apointer 1020 on one side. The pointer 1020 is disposed on a side of thedriver 540 opposite of the side upon which the wedge portion 394 if thebaseplate 54A includes the planar portion 390. If the baseplate 54A is afull wedge configuration, the thickest portion of the wedge is disposedaway from the pointer 1020, e.g., at the location of the dashed arrow inFIG. 27G. With the baseplate 54A so placed, the inner shaft 548 can berotated about a central longitudinal axis thereof to advance a screwsuch as the screw 577 or other central anchor can be secured in thecentral area of the glenoid 18. Advancing the screw 577 occurs while thepointer 1020 of the outer shell 544 continues to point at the mark 1014.The result is that the baseplate 54A remains in a rotationallystationary position, oriented according to the preoperative plan. Thisensures that the wedge portion 394 of the baseplate 54A is aligned tothe posterior side away from the location of the glenoid guide 1050.FIG. 27H shows this result after the driver 540 has been removed. In theillustrated embodiment, the thickest portion of the baseplate 54A, e.g.,the wedge portion 394 is disposed posteriorly and somewhat inferiorly ofthe thinnest portion the baseplate 54A in the case of a full wedgebaseplate. In the case of a partial wedge baseplate 54A such as wherethe augment is only on one-half (or less) of the baseplate 54A, as muchas 180 degrees (or more) of the baseplate 54A will have the samethickness in the non-augmented periphery and each portion along thenon-augmented periphery will correspond to the least thickness of thebaseplate 54A. For partial wedge baseplates, the thickest portion of thebaseplate 54A can be disposed posteriorly and somewhat inferiorly of thecenter of the circumference of the non-augmented periphery using themethod illustrated in FIG. 27A-27H. These positions and orientations areas prescribed from pre-operative imaging. In some cases, the boundarybetween the wedge portion 394 and the planar portion 390 can be at anangle to the superior-inferior plane of the glenoid 18, as prescribedfrom pre-operative imaging.

The mark 1014 is illustrated as being used to rotationally orient thebaseplate 54A during insertion thereof. The mark 1014 can also be usedto guide the advancement of the reamer 404 either free-hand or over theguide pin 204. A pointer on the reamer 404 can be aligned with the mark1014 to cause the reaming head 412 to be in a desired position, e.g., apre-determined amount off-set therefrom e.g., 180 degrees off-settherefrom. In further variations, the guide pin 208 can be placedthrough the channel 1010 and the reaming guides 432, 432A can beconfigured to mate with the pin 208 so placed.

FIGS. 28A and 28B illustrate a glenoid guide 1050 that is similar to theglenoid guide 1000 except as described differently below. The glenoidguide 1050 includes a plurality of peripheral members 108 and alsoincludes a peripheral member 108R configure for forming a mark 1064 orother rotation control feature. The peripheral member 108R provides achannel 1060 for making the mark 1064. Unlike the peripheral channel1010, the channel 1060 is open on one side. The channel 1060 is enclosedon a side radially between the hub 104 and the radially outer-mostportion of the peripheral members 108. The channel 1060 is open on theoutermost radial periphery of the peripheral member 108R.

One advantage of the glenoid guide 1050 is that by providing an openchannel 1060, the mark 1064 can be elongate. For example, the mark 1064can be formed by directing a marker along the enclosed wall of thechannel 1060 until the marker contacts the scapula 14. The marker canthen be moved in a direction along the axis of the peripheral member108R as shown by the arrow 1066 to configure the mark 1064 as elongatedin the direction of the arrow 1066. The elongated form of the mark 1064can enhance the ability of the surgeon to accurately align the pointer1020 with the mark 1064, further enhancing the alignment of the wedgeportion 394 of the baseplate 54A (or more generally the thickestportion) with the angled reamed surface R2 or other portion of theglenoid 18 that would benefit from the greatest amount of augmentation.

The mark 1064 can also be used to guide the advancement of the reamer404 either free-hand or over the guide pin 204. A pointer on the reamer404 can be aligned with the mark 1064 to cause the reaming head 412 tobe in a desired position, e.g., 180 degrees off-set therefrom. Infurther variations, the guide pin 208 can be placed through the channel1060 and the reaming guides 432, 432A can be configured to mate with thepin 208 so placed.

As discussed above, in connection with the patient specific shoulderguide 100, the glenoid guide 1000 and the glenoid guide 1050 can beformed using a protocol in which patient specific imaging information isgathered and processed. The processing can include inputs from thesurgeon such as whether the surgeon wishes to use a bovie pen, drillbit, pin or the like to create a visual reference opposite the portionof the glenoid to be most augmented. The processing can includedetermining whether features can be formed in one of the peripheralmembers 108 configured to make patient specific contact with the glenoidrim 17 or should be disposed in a separate peripheral member. In oneapproach, the rotational position of one of the peripheral members 108can be selected to be opposite to, e.g., 180 degrees off-set from theportion of the glenoid to be most augmented. Next either the surgeon orthe protocol determines whether to form an enclosed channel, as in theperipheral channel 1010, or an open sided channel or slot, as in thechannel 1060, in the peripheral member 108R. Next the protocol canoutput plans for forming the glenoid guide 1000 or the glenoid guide1050. Upon outputting the plans, the glenoid guide 1000 or the glenoidguide 1050 can be produced using a preferred facility such as additivemanufacturing or other guide forming process. In some embodiments a kitincluding at least the glenoid guide 1000 and the glenoid guide 1050 canbe formed such that the surgeon can select whether to use a closedchannel or an open channel, e.g., a slot to form a bovie mark on or achannel in or to place a pin in the bone.

V. Enhanced Access Glenoid Guides

FIGS. 1, 1A and 19 illustrate challenges of surgically accessing theglenoid 18 with a glenoid guide GG, which can be patient specific. Theglenoid guide GG can be configured with at least a portion that extendstoward the posterior side of the glenoid 18. The glenoid guide GG isadapted to mate with a pin guide 590. The pin guide 590 includes anelongate body having a tapered distal portion 592 that extendsproximally from a distal end thereof. The tapered distal portion 592 canmate with a tapered central channel of the glenoid guide GG. The pinguide 590 includes a pin guide lumen 594 that can be aligned with thechannel in the glenoid guide GG. The pin guide 590 enables the centralguide pin 204 or other pin (e.g., a Steinmann pin, a K-wire, or anothersimilar slender but rigid guide pin) to be placed along a longitudinalaxis 596 of the pin guide 590. When placed on the glenoid 18, theglenoid guide GG stands at a height above the surface of the glenoid 18.The height of the glenoid guide GG is uniform throughout the guide. Theheight of the glenoid guide GG affects the stability of the pin guide590. By increasing the height of the glenoid guide GG, a largerinterface between the pin guide 590 and the central channel of theglenoid guide GG can be provided for increased stability. However,increased height may result in interference between the glenoid guide GGand the retractor 16 or other instruments, which can result in damage ordisplacement of the glenoid guide GG from the proper orientation.

FIGS. 20-26 show embodiments of glenoid guides that provide enhancedaccess in the surgical field around the glenoid 18. These guides can bepatient specific. As discussed above in connection with the guide 100,the guides herein described below can have central and peripheralmembers. The size and/or placement or orientation of the central orperipheral members or the gross dimensions of the guides described belowcan be patient specific. Medial bone contacting surfaces of the guidesdescribed below can be patient specific, e.g., having complementary formthat may be concave or otherwise a substantial negative of specificunderlying bone. As above-described, pre-operative scans can be utilizedto configure patient specific surfaces to be complementary, e.g.,negative, surfaces of the bone to which they are to mate such that theguide is seated according to the optimized fit as determined by thesurgeon. The guides can be low profile in a number of different ways.For example, FIGS. 20-22A show guides in which a portion that extendsinto a posterior region of the glenoid 18 when applied has a lesserheight, lesser length, e.g., extends a lesser amount in a direction awayfrom the glenoid (e.g., in a vertical direction if the patient is placedon his or her side) when compared to at least some other portions of theguides. As used herein, the term “low profile” refers to this and otheraspects in which the guides herein can be confined out of the way ofother instruments to be used in the procedure. FIGS. 23-24B show guideswhere a plurality of peripheral members is of a low profile and acentral portion extends above or below the members to mate in a stablemanner with the pin guide 590. FIGS. 24-24B illustrate guides in which aposterior portion is shorter than in other configurations herein andthus can be configured to mate with a glenoid surface disposed inward ofa glenoid rim. FIGS. 25A-26B illustrate guides with peripheral membersconfigured to contact a glenoid structure are disposed in an anteriorportion but not in a posterior portion of the guide.

A. Low Profile Glenoid Guides Having Reduced Proximal Height Features

FIGS. 20-22A show guides in which a portion that extends into aposterior region of the glenoid 18 when applied extends a lesser amountin a lateral direction (away from the surface of the glenoid) whencompared to at least some other portions of the guides. In other words,a portion of the glenoid guide occupies less space with regard to atleast one length dimension or distance (e.g., radial length, height,and/or circumferential width) compared to other portions of the guides.The glenoid guides can extend proximally or laterally a lesser amount inan anterior portion, in a posterior portion, in an inferior portion, orin a superior portion than other portions. For example, a posteriorportion of the surgical field can be made less obstructed by limitingthe lateral extent, length, distance or height of glenoid contact pointsof a guide.

FIGS. 20-20B show a patient specific shoulder guide 600 that isconfigured to provide enhanced access for instruments such as theretractor 16 that is or are disposed posteriorly of or over a posteriorportion of the shoulder guide 600. The shoulder guide 600 is shown on aschematic representation of a glenoid 18 of a scapula 14. By enhancingaccess to the anatomy around a posterior portion of the glenoid 18 (andalso posterior thereto), the guide 600 enables the use of the retractor16 and other instruments without interference between the patientspecific shoulder guide 600 and such instruments.

The patient specific shoulder guide 600 includes a hub 604 and aplurality of peripheral members 608. The peripheral members 608 can bedispersed into a posterior portion 612 and an anterior portion 616 ofthe patient specific shoulder guide 600. In one embodiment, there is aplurality of (e.g., three) peripheral members 608 in the anteriorportion 616 and there is at least one (e.g., only one) one peripheralmember 608 in the posterior portion 612. The posterior portion 612 canbe defined as the portion of the patient specific shoulder guide 600that would align with a posterior side of the glenoid 18 when applied toa specific patient. The posterior portion 612 can be to the posteriorside of a plane intersecting the hub 604 and extending generallysuperior and inferior when the patient specific shoulder guide 600 isapplied to a patient. The patient specific shoulder guide 600 that isdepicted would be suitable for a left shoulder joint of a specificpatient.

As discussed further below, some embodiments can have as few as threecontact points, e.g., three peripheral members 608 to define a stableposition. Also in some embodiments, the shoulder guide 600 has no morethan three peripheral members 608. A fourth contact point, e.g., afourth peripheral member 608 of a fourth contact point in thearticulating surface of the glenoid, provides an advantage of confirmingthat the patient specific shoulder guide 600 is properly positioned. Forexample, in an embodiment having four peripheral members, if a user wereto find that only three of four contact points made contact one canconclude that a problem has arisen, such as the patient specificshoulder guide 600 is not properly positioned, has been distorted, etc.

FIGS. 20A and 20B shows that the hub 604 includes a first end 620 and asecond end 624. The first end 620 is configured to face a centralsurface of the glenoid 18. The second end 624 is disposed oppose thefirst end 620, e.g., away from the glenoid 18. A hub body 628 extendsbetween the first end 620 and the second end 624 and defines a hubheight dimension 632. The hub 604 includes a central channel 636disposed therethrough. The central channel 636 can be coupled with thepin guide 590 to provide a guide conduit that includes the pin guidelumen 594 and may include a portion extending through the centralchannel 636. In some embodiments of the patient specific shoulder guide600 and of the other glenoid guides disclosed herein it is desired toprovide the hub height dimension 632 above a threshold or minimumdimension. In some embodiments, the second end 624 is disposed at theproximal most part of the patient specific shoulder guide 600.Maintaining the hub height dimension 632 above a minimum dimensionensures that the contact region with the pin guide 590 is sufficient toreduce, minimize or eliminate deviation of the longitudinal axis 596(and thus the trajectory of the pin placed through the pin guide 590)from the intended trajectory. The hub height dimension 632 can bemaintained the same or can be no shorter than sufficiently long toprovide this control of the intended trajectory.

The peripheral members 608 can each include an inner end 650, an outerend 654 and an elongate member 656 extending therebetween. A structureforming a patient specific contact surface 658 can be coupled with orcan extend from or comprise a portion of the outer end 654. FIG. 20Bshows that the patient specific contact surface 658 can be highlycontoured to receive, to mate with, to follow, and in some cases to beformed as a negative of a natural bone surface of glenoid 18. Thepatient specific contact surface 658 can be highly contoured to receive,to mate with, to follow, and in some cases to be formed as a negative ofa portion of the rim of the glenoid 18, an osteophyte otherprotuberances of the rim or other portion of or adjacent to the glenoid18, or another portion of the scapula 14 close to the rim of the glenoid18. A peripheral member height dimension 662 can be defined in aproximal-distal direction (which also is a medial-lateral direction awayfrom the glenoid 18 when applied to the patient). The peripheral memberheight dimension 662 can be measured in one embodiment as the distancebetween a distal-most aspect of the patient specific contact surface 658and a side 666 of the patient specific shoulder guide 600 opposite thepatient specific contact surface 658.

In one embodiment, the patient specific shoulder guide 600 is formed byadditive manufacturing. A high profile portion of the shoulder guide 600provides a co-planar relationship between the second end 624 of the hub604 and adjacent sides of each of a plurality of the peripheral members608. These co-planar portions can be disposed on the same side 666. Inone embodiment, the entire sided side 666 of the patient specificshoulder guide 600 is on a common plane other than a low profileportion. The low profile portion can include a low profile peripheralmember 670. The low profile peripheral member 670 can include an innerportion 674 and outer portion 678 and an elongate member 682 thatextends therebetween. At least the outer end 678 and preferably theentire low profile peripheral member 670 has a peripheral heightdimension 690 that is less than, e.g., 75% lower than, in some cases 50%lower than, and in some cases 25% lower than, the peripheral memberheight dimension 662. As shown in FIG. 20B the peripheral heightdimension 690 can be defined between the patient specific contactsurface 658 of the low profile peripheral member 670 and a side 692opposite the patient specific contact surface 658 of the low profileperipheral member 670. In one embodiment, the side 692 of the lowprofile peripheral member 670 is at a lower height than the side 666 ofthe elongate member 656 of the other peripheral members 608. In oneembodiment, the side 692 of the low profile peripheral member 670 is ata lower height than the second end 624 of the hub 604. The low profileof the peripheral member 670 allows the retractor 16 to have greateraccess in the portion of the glenoid 18 over which the posterior portion612 of the patient specific shoulder guide 600 extends or is disposedand to portions of the scapula that a posterior to that location. Thisallows the retractor 16 to be positioned posterior to the glenoid 18 andmove soft tissue out of the surgical field to provide access to theglenoid 18 of the patient without risk of disruptive contact between theretractor 16 and the patient specific shoulder guide 600.

FIGS. 21-21B illustrate a low profile patient specific shoulder guide700 that is similar to the guide 600 except as described differentlybelow. The patient specific shoulder guide 700 is configured to provideenhanced engagement with a portion of a glenoid rim. The patientspecific shoulder guide 700 is configured to provide enhanced stabilityon one side of the glenoid 18. The patient specific shoulder guide 700includes a posterior side 702 and an anterior side 704. The posteriorside 702 and the anterior side 704 are each disposed away from a hub 706which is generally centrally located on the patient specific shoulderguide 700. The posterior side 702 extends from the hub 706 to a locationover a posterior portion of the glenoid 18 when applied to the scapula14. The anterior side 704 extends from the hub 706 to a location over ananterior portion of the glenoid 18 when applied to the scapula 14. Thehub 706 is also disposed at a center of a plurality of peripheralmembers 708. The peripheral members 708 can each be coupled with anoutside surface of the hub 706. The peripheral members 708 can extendradially away from the hub 706.

The peripheral members 708 can each include an inner end 712 and anouter end 716. The inner ends 712 can be directly coupled with the hub706. The outer end 716 can be disposed away from the inner end 712 andaway from the hub 706. In the illustrated embodiment, the posterior side702 includes one peripheral member 708 and the anterior side 704includes a plurality of, e.g., three, peripheral members 708. Othernumbers of peripheral members 708 can be provided. Other distributionsof peripheral members 708 can be provided. As in other guides herein,more than one peripheral member 708 can be provided in the posteriorside 702 and fewer than three peripheral members 708 can be provided inthe anterior side 704 of the patient specific shoulder guide 700.

The hub 706 can have a central channel 736 that extend therethrough. Thecentral channel 736 can provide access for the pin guide 590 asdiscussed above in connection with the patient specific shoulder guide600. The patient specific shoulder guide 700 also can have a side member740 through which a side channel 744 is disposed. The side channel 744can be configured to allow a pin to be placed therethrough into theglenoid 18. The side channel 744 thus allows access for a device tocontrol rotation of patient specific shoulder guide 700 while in use.

In one embodiment, one or more of the hub 706, the side member 740, andthe peripheral members 708 disposed on the anterior side 704 of thepatient specific shoulder guide 700 have proximal portions that aredisposed in a common plane. In other words, height dimension of each ofthese components are measured from a common proximal plane. In onevariation the proximal portion of each of the hub 706, the side member740, and the peripheral members 708 is disposed in a common plane. Theperipheral member 708 disposed in the posterior side 702 of the patientspecific shoulder guide 700 has a low profile. The low profile issimilar to the low profile of the peripheral members 608 in theposterior portion 612 of the patient specific shoulder guide 600 asdiscussed above. That is the peripheral height dimension 690 of theperipheral members 708 in the posterior side 702 is much less than theperipheral member height dimension 662 of the peripheral members 708 inthe anterior side 704 of the patient specific shoulder guide 700.

In one variation the peripheral member 708 in the posterior side 702includes an elongate member 720 disposed between the inner end 712 andthe outer end 716. A peripheral elongate member 722 can be disposed ator adjacent to the outer end 716 of the peripheral members 708 onposterior side 702 of the patient specific shoulder guide 700. Theperipheral elongate member 722 can have a patient specific contactsurface 724 that is formed by reference to CT scan images or the likethat can be obtained pre-operatively, as discussed above. The patientspecific contact surface 724 preferably is a substantial negative of anelongate zone of the rim of the glenoid 18. In one embodiment, theperipheral elongate member 722 includes an inferior end 728 and asuperior end 732. The peripheral elongate member 722 can span a largeportion of the rim of the glenoid 18 compared to the contact features ofthe peripheral members 708 on the anterior side 704 of the patientspecific shoulder guide 700. In one embodiment, the peripheral elongatemember 722 has an inferior-superior extent that is at least three timesthe largest dimension of, e.g., the diameter of, the contact feature ofthe other peripheral members 708. In one embodiment, the peripheralelongate member 722 has an angle between lines centered on the center ofthe central channel 736 and tangentially contacting the inferior end 728and the superior end 732 is greater than 5 degrees, or is greater than10 degrees, or is greater than 15 degrees, or in some cases greater than20 degrees. The angle between lines centered on the center of thecentral channel 736 and tangentially contacting the inferior end 728 andthe superior end 732 can be between about 5 degrees and about 60degrees, e.g., between about 10 and about 45 degrees, between about 15and about 35 degrees.

The patient specific shoulder guide 700 can perform similar to thepatient specific shoulder guide 600 in being low profile and notinterfering with the retractors 16 and other instruments in the surgicalfield. The patient specific shoulder guide 700 can provide an additionaladvantage in reducing unwanted movement of the patient specific shoulderguide 700 on the glenoid 18. The surface area of contact of theperipheral elongate member 722 is much greater than that in the outerend 678 of the elongate member 682 of the patient specific shoulderguide 600. This is achieved without additional elongate members 720,which allows the access to the glenoid 18 to remain relatively open andunobstructed. Also, by increasing the surface area of contact forcesapplied to the patient specific shoulder guide 700 are spread out morelessening the pressure on the contact area on the rim of the glenoid 18.

FIGS. 22 and 22A show another embodiment of a patient specific shoulderguide 770 that has a low profile peripheral member 774. The peripheralmember 774 is shown in FIG. 22A. It has a low profile peripheral heightdimension 690 compared to a high profile peripheral member heightdimension 662. The patient specific shoulder guide 770 can be similar tothe guides hereinbefore described except as where described differentlybelow.

The patient specific shoulder guide 770 includes a hub 772 from whichthe peripheral members 774 extend radially. Each of the peripheralmembers 774 has an inner end 776, an outer end 778 and an elongatemember 780 therebetween. At least one of the peripheral members 774 isadapted for enhanced patient specific contact. For example, a peripheralmember 774 in the posterior side of the patient specific shoulder guide770 can include a rim engaging portion 782 and a glenoid surfaceengaging portion 784. The rim engaging portion 782 can be similar to therim engaging portions discussed above in various other guides. Theglenoid surface engaging portion 784 can comprise a portion of theelongate member 780 between the inner end 776 and the outer end 778. Inone embodiment, the peripheral members 774 are configured based on CTscan images or the like obtained pre-operative with a continuous patientspecific contact zone that extends from the rim engaging portion 782 tothe glenoid surface engaging portion 784. The continuous patientspecific contact zone can extend up to one-half the distance from therim of the glenoid 18 to the hub 772. The continuous patient specificcontact zone can extend at least sixty percent of the distance from thehub 772 to a portion of the patient specific shoulder guide 770 adaptedto contact an outside of the rim of the glenoid 18 when applied. Thecontinuous patient specific contact zone can extend at least seventypercent of the distance from the hub 772 to a portion of the patientspecific shoulder guide 770 adapted to contact an outside of the rim ofthe glenoid 18 when applied.

The patient specific shoulder guide 770 can be configured such that theentire distal surface of at least one of the peripheral members 774,e.g., of the posterior side peripheral member 774, is in contact withthe glenoid rim or surface in a patient-specific manner, e.g., as anegative of those natural surfaces. In one variation, one peripheralmember 774 is configured in this manner and two additional peripheralmembers 774 for a total of only three peripheral members 774 areprovided to provide patient specific contact with the glenoid rim. Wherethe peripheral member 774 is configured to be in contact with theglenoid 18, the peripheral member 774 can be configured to contact thesub-chondral surface. The peripheral member 774 can be configured tocontact a cartilage surface over the articular surface of the glenoid18.

FIG. 22 shows that in one embodiment, the distal end of the hub 772 isspaced proximally of the glenoid surface engaging portion 784 of theperipheral member 774 configured to contact the glenoid 18. A step canbe provided between the distal face of the glenoid surface engagingportion 784 and the distal face of the hub 772. The step enables theportion of the hub 772 closest to the glenoid to be spaced way from andnot contact the glenoid while a portion 778 of the glenoid surfaceengaging portion 784 is in direct contact with the glenoid adjacent tothe step. The hub 772 has a central channel 790 disposed therethroughconfigured to mate with the pin guide 590 and/or receive a guide pintherethrough into the glenoid 18.

The patient specific shoulder guide 770 can include aside member 792having a side channel 794 therethrough for placement of a pin forstabilizing the patient specific shoulder guide 770 in rotation.

The patient specific shoulder guide 770 is advantageous in that theamount of surface area of contact is greatly increased due to some orall of the length of the elongate member 780 on the posterior side ofthe patient specific shoulder guide 770 being in contact with theglenoid 18. The contact can allow the patient specific shoulder guide770 to be made of a wider range of materials because the contact nearthe hub 772 reduces flexing of the patient specific shoulder guide 770when the pin guide 590 is docked with the central channel 790. Byreducing or eliminating flexing the trajectory of a guide pin through apin guide 590 mated along the central longitudinal axis of the centralchannel 790 is better controlled, e.g., closer to the true trajectorythat prescribed based on CT scan imaging or the like taken preoperative.

FIGS. 23-24B show embodiments of a patient specific shoulder guide 800in which at least a plurality of peripheral members are lowered or arelow profile to reduce or minimize the space needed to accommodate theguides. The patient specific shoulder guide 800 allows greater access toanterior and posterior, as well as to inferior and to superior regionsof the glenoid 18 when the patient specific shoulder guide 800 isapplied to the scapula 14 of a patient.

FIG. 23 shows that more than one of a plurality of peripheral members808 are made low profile in the patient specific shoulder guide 800. Thepatient specific shoulder guide 800 includes a posterior portion 802 andan anterior portion 804. The posterior portion 802 includes oneperipheral member 808 and the anterior portion 804 includes a pluralityof, e.g., three, peripheral members 808. The peripheral members 808extend radially away from a hub 806.

An outer end of the peripheral members 808 includes or is coupled with amember providing a patient specific contact surface 812. The patientspecific contact surface 812 can be configured to mate with specificportions of the glenoid 18 or the scapula 14 based on preoperativecharacterization by CT scan or the like, as discussed above. The hub 806defines a central channel 820. The central channel 820 is configured tomate with the pin guide 590 as discussed above in connection with otherguides. The patient specific shoulder guide 800 includes a side channel828 that extends therethrough from a proximal side to a distal portionthereof. The side channel 828 can be formed in aside member 824 of thehub 806. The side channel 828 can be configured to receive an anchor pinor member. The patient specific shoulder guide 800 can be stabilized bythe placement of a pin through the side channel 828. In a variation, theside member 824 is elongated to enable placement of a peripheral pinsuch as the peripheral guide pin 208.

FIGS. 23 and 23B show that each of the peripheral members 808 extendfrom a common plane which can intersect a proximal side 832 of eachmember 808. As a result, the entire portion of the patient specificshoulder guide 800 radially outward of the hub 806 is low profile. Thiscan be seen in comparing the height dimension 690 from a patient contactsurface to lateral side 832 to the height dimension 834 from a patientcontact surface to a lateral side of the hub 806. The height dimension690 is much less than the height dimension 834 which enables theperipheral members 808 to be generally out of the way of surgicalinstruments around the periphery of the glenoid. The low profile portionof the patient specific shoulder guide 800 extends into the posteriorportion 802 and in the anterior portion 804. This enables the retractor16 and other surgical instruments on both sides of the patient specificshoulder guide 800 to have greater freedom of movement without impingingon or otherwise interacting with the patient specific shoulder guide800. FIG. 23B shows that the entire peripheral region has the lowprofile peripheral height dimension 690. Also, the hub 806 is configuredto extend above (e.g., proximally or laterally of) the proximal side832. The hub 806 thus benefits from a high profile central heightdimension 834. By elevating a proximal end of the hub 806, an interfaceregion of the hub 806 can remain sufficiently elongated to provide forstable connection with the pin guide 590 so that good control of thetrajectory of the longitudinal axis 596 of the pin guide 590 ismaintained as discussed above.

FIGS. 24-24B show a patient specific shoulder guide 850 that is similarto the patient specific shoulder guide 800 in providing low profileperipheral members. The hub 856 of the patient specific shoulder guide850 is configured not to extend above a lateral side 874 that resides ina plane that includes the proximal sides of glenoid rim members 858 ofthe guide 850. As discussed more fully below, the hub 856 of the patientspecific shoulder guide 850 is configured to project medially of amedial side 876 of the glenoid rim members 858. More particularly, thehub 856 includes a medial end 857 that is significantly medial of themedial side 876 of the glenoid rim members 858. As used herein “medial”refers to being closer to the midline of a patient when the guide 850 iscoupled with the glenoid rim than another portion that is less medial orthat is more lateral with respect to the midline of a patient. As aresult, the proximal-distal length of the hub 856 can be similar in theguide 850 as in hub 806 of the guide 800. Thus, even though the hub 856does not project laterally of the lateral side 874 the patient specificshoulder guide 850 can achieve similar control over the longitudinalaxis 596 of the pin guide 590 when docked with a central channel of thehub 856 as is achieved in the guide 800. The patient specific shoulderguide 850 can also be easily manufactured using additive manufacturingbecause all of the features of the guide 850 on the proximal sidethereof reside in a common proximal plane as is seen in FIG. 24B.

B. Low Profile Glenoid Guides with Reduced Glenoid Rim Contact

FIGS. 24-26B also illustrate further embodiments of patient specificshoulder guides in which the profile thereof can be reduced by reducingthe radial extent of or to eliminate one or more of a plurality ofperipheral members to enhance access for the retractors 16 or for othersurgical instruments that may be deployed in the surgical field.

1. Glenoid Guides with Shortened Peripheral Members

The patient specific shoulder guide 850 has been discussed in somedetail above. Further unique features of the patient specific shoulderguide 850 include providing diverse configurations of peripheral membersthereof. The patient specific shoulder guide 850 includes one or aplurality of glenoid rim members 858. The glenoid rim members 858 areadapted to contact a rim of a glenoid 18 of a specific patient, in muchthe same way as other guides described above. FIG. 24 shows each ofthree glenoid rim members 858 disposed on the peripheral rim of theglenoid 18. The distal surfaces of the outer ends of one or more of,e.g., each of, the glenoid rim members 858 has patient specific contourson a glenoid rim contact surface 862, similar to the guides discussedabove. In other embodiments one or more of the glenoid rim members 858are configured to contact structures around the glenoid 18, e.g., in thescapula 14 outside the rim of the glenoid 18. The patient specificshoulder guide 850 also includes one or more glenoid surface member 866.The glenoid surface member 866 is configured to contact a surface or astructure of the glenoid 18 disposed radially inward of the rim thereof.The glenoid surface member 866 can be configured to contact sub-chondralbone at a glenoid surface contact surface 870. The glenoid surfacemember 866 can be configured to contact the cartilage in the naturalarticular surface of the glenoid 18.

The patient specific shoulder guide 850 includes more than three contactsurfaces which provides several advantages. Three contact surfaces,e.g., the glenoid rim contact surfaces 862, provide sufficient stabilityof a guide on a natural surface like the glenoid 18. By adding thefourth contact surface at glenoid surface contact surface 870 thesurgeon can confirm that the procedure should continue with the patientspecific shoulder guide 850. Furthermore, FIG. 24 shows that the glenoidsurface member 866 can be positioned close in a radial direction to thehub 856 than are the contact surfaces of the glenoid rim members 858.The distance from the inner to the outer end of the glenoid surfacemember 866 can be much less than even the shortest of the glenoid rimmembers 858. As a result, the glenoid surface member 866 providesadjacent support for the hub 856. The adjacent support transfers distalforces and pressures that are applied when the pin guide 590 is coupledwith a central channel 878 with the patient specific shoulder guide 850to the surface of the glenoid 18. The radial shortness of the glenoidsurface member 866 allows this force and pressure transfer with minimalto no flexing in the glenoid surface member 866. Thus control of thelongitudinal axis 596 of the pin guide 590 is maintained or enhanced.Further, by moving this contact point radially inward of the glenoidrim, the peripheral member may be removed from interference with othersurgical instruments.

As in other guides herein, the patient specific shoulder guide 850 canoptionally have aside member 880 disposed adjacent to the centralchannel 878. The side member 880 can have a side channel 884 disposedtherethrough. The side channel 884 can be configured to receive a pin orother structure configured to manage or help to maintain minimalrotation of the patient specific shoulder guide 850 relative to theglenoid 18. FIG. 24B shows that the side member 880 can be low profilesuch that the entire guide side member 880 has a proximal height that isreduced in addition to the radial extend of the glenoid surface member866 be reduced compared to the glenoid rim members 858.

The patient specific shoulder guide 850 is also advantageous in thateven the hub 856 is made low profile while maintaining the control ofthe pin guide 590. As a result, the hub 856 does not interfere with theretractor 16 or other instruments that are passed between the posteriorportion 852 and the anterior portion 854 or between a superior and aninferior side of patient specific shoulder guide 850 or of the glenoid18. The lower profile nature of the patient specific shoulder guide 850can also enable the surgeon to retract the tissue less and to shortenthe incision used to access the glenoid 18.

2. Glenoid Guides with Restricted Rim Contact Zones

FIGS. 25A-26B illustrate embodiments of glenoid guides in which reliableplacement of the central guide pin 204 can be achieved while leavinglarge regions of a glenoid exposed without obstruction.

FIG. 25A shows a patient specific shoulder guide 900 that includes aposterior portion 902 and an anterior portion 904. The patient specificshoulder guide 900 can be similar to other guides described above exceptas described differently below. For example, the anterior portion 904can be similar to the anterior regions of other guides described above.The anterior portion 904 can include a plurality of glenoid rim members908. The glenoid rim members 908 can extend from a hub 906 that islocated centrally to the glenoid rim members 908. The glenoid rimmembers 908 can include elongate members with inner and outer ends,similar to the structures described above. The outer ends of each of theglenoid rim members 908 can be configured with a patient specificcontact surface 912 disposed on or coupled therewith. The patientspecific contact surface 912 can be made based on pre-operative CT scanimaging or the like as discussed above.

In some variations, the shoulder guide 900 or other guides disclosedherein can be configured with no more than 3 peripheral legs, such asfor example in connection with FIGS. 26A and 26B. In one variation theguide 950, discussed further below has no peripheral legs in a posteriorportion of the guide 950. In one variation all of the legs are disposedin the anterior portion of the guide 950. Furthermore, in somevariations the guides disclosed herein can be configured at least inpart based on surgeon preference, patient needs, or both surgeonpreference and patient needs to leave another portion, e.g., ananterior, superior, or inferior portion without any legs present in thator those portions. A portion can be defined between two or moreportions, e.g., superior-posterior, inferior-posterior,superior-anterior, inferior-anterior, etc.

The patient specific shoulder guide 900 can also include a centralmember 914. The central member 914 is coupled with or can be anextension of the hub 906. The central member 914 can surround alongitudinal axis of a central channel 924 that is disposed through thepatient specific shoulder guide 900, e.g., through the hub 906 and thecentral member 914. The central member 914 includes a patient specificcontact surface 918. The distal face of the central member 914 can bepatient specific. The central member 914 can include an annular contactface that is formed based on a specific patient's anatomy toward thecentral region of the glenoid 18 of the patient. The distal face of thecentral member 914 can be generally convex to follow the generallyconcave surface of sub-chondral bone. The distal face of the centralmember 914 can be formed to follow cartilage if mating the centralmember 914 to the cartilage is preferred. In one embodiment the glenoidrim members 908 and the central member 914 are configured to conform tobone, e.g., as negatives of the natural bone anatomy, includingosteophytes. In one embodiment one or more of the glenoid rim members908 and the central member 914 can be configured to conform withcartilage while the other of the glenoid rim members 908 and the centralmember 914 can be configured to conform to bone, e.g., as negatives ofthe natural bone anatomy, including osteophytes.

The central member 914 can include a circular contact profile. Thepatient specific contact surface 918 can extend from an outer peripheryof the central channel 924 to an outer periphery of the central member914. The outer periphery of the central member 914 can be circular. Thediameter of the outer periphery can be sized to provide sufficientstability of the patient specific shoulder guide 900 to tipping.

The patient specific shoulder guide 900 can include an side member 926.The side member 926 can have a side channel 928 disposed therethrough.The side channel 928 can be used to place an anti-rotation device suchas a pin into the glenoid. The central channel 924 can be used to placethe central guide pin 204. In one modified embodiment, the side member926 is eliminated. The modified embodiment may be configured with alarger diameter outer periphery of the central member 914 to providegreater stability in the absence of a pin which could be placed throughthe side member 926.

The patient specific shoulder guide 900 is advantageous in leaving alarge span 930 of the surgical field un-obstructed. For example, a span930 of more than 120 degrees can be unobstructed by the presence of aglenoid rim member 908. In some embodiments, a span 930 of more than 130degrees can be unobstructed by the presence of a glenoid rim member 908.In some embodiments, a span 930 of more than 140 degrees can beunobstructed by the presence of a glenoid rim member 908. In someembodiments, a span 930 of more than 150 degrees can be unobstructed bythe presence of a glenoid rim member 908. In some embodiments, a span930 of more than 160 degrees can be unobstructed by the presence of aglenoid rim member 908. In some embodiments, a span 930 of more than 170degrees can be unobstructed by the presence of a glenoid rim member 908.In some embodiments, a span 930 of more than 180 degrees can beunobstructed by the presence of a glenoid rim member 908. In someembodiments, a span 930 of more than 190 degrees can be unobstructed bythe presence of a glenoid rim member 908. In some embodiments, a span930 of more than 200 degrees can be unobstructed by the presence of aglenoid rim member 908. In some embodiments, a span 930 of more than 210degrees can be unobstructed by the presence of a glenoid rim member 908.In some embodiments, a span 930 of more than 220 degrees can beunobstructed by the presence of a glenoid rim member 908. In someembodiments, a span 930 of more than 230 degrees can be unobstructed bythe presence of a glenoid rim member 908. In some embodiments, a span930 of more than 240 degrees can be unobstructed by the presence of aglenoid rim member 908. In some embodiments, a span 930 of more than 250degrees can be unobstructed by the presence of a glenoid rim member 908.In some embodiments, a span 930 of more than 260 degrees can beunobstructed by the presence of a glenoid rim member 908. In someembodiments, a span 930 of between 180 degrees and 260 degrees can beunobstructed by the presence of a glenoid rim member 908.

In some embodiments, the glenoid rim members 908 can be disposed in azone of less than 180 degrees of the patient specific shoulder guide900. In some embodiments, the glenoid rim members 908 can be disposed ina zone of less than 170 degrees of the patient specific shoulder guide900. In some embodiments, the glenoid rim members 908 can be disposed ina zone of less than 160 degrees of the patient specific shoulder guide900. In some embodiments, the glenoid rim members 908 can be disposed ina zone of less than 150 degrees of the patient specific shoulder guide900. In some embodiments, the glenoid rim members 908 can be disposed ina zone of less than 140 degrees of the patient specific shoulder guide900. In some embodiments, the glenoid rim members 908 can be disposed ina zone of less than 130 degrees of the patient specific shoulder guide900. In some embodiments, the glenoid rim members 908 can be disposed ina zone of less than 120 degrees of the patient specific shoulder guide900. In some embodiments, the glenoid rim members 908 can be disposed ina zone of less than 110 degrees of the patient specific shoulder guide900. In some embodiments, a span of between 45 degrees and 180 degreescan enclosed all of the glenoid rim members 908.

FIGS. 26A and 26Bf illustrate a patient specific shoulder guide 950 thatis similar to the patient specific shoulder guide 900 except asdescribed differently below. The patient specific shoulder guide 950also includes a posterior portion 952 that is free of glenoid rimmembers 958. The shoulder guide 950 is configured such that it consistsessentially of glenoid contact members that are anterior of a posteriorportion of the glenoid rim, e.g., are in a central region of the glenoidand/or in the anterior region of the glenoid rim. The patient specificshoulder guide 950 has an anterior portion 954 in which the glenoid rimmembers 958 are disposed. Each of the glenoid rim members 958 includes apatient specific contact surface 962 coupled with or disposed at outerends of an elongate member thereof. The patient specific shoulder guide950 thus retains an unobstructed the posterior portion 952 allowing theretractor 16 and other instruments free access to the posterior portionof the glenoid 18. The extent of the unobstructed posterior portion 952can be similar to the extent of the unobstructed posterior portion 902as discussed above in connection with the patient specific shoulderguide 900. The bounds of a zone of the anterior portion 954 thatcontains the glenoid rim members 958 can be similar to the bounds of thezone of the anterior portion 904 that contains the glenoid rim members908.

The patient specific shoulder guide 950 includes a hub 956 through whicha central channel 984 extends. A patient specific contact surface 962can be disposed at or coupled with a distal portion of the hub 956. Thepatient specific contact surface 962 includes a patient specific contactsurface 968 that is formed by reference to the specific patient. Thepatient specific contact surface 962 also can be configured to reduceflexing in or rotation of the patient specific shoulder guide 950 inuse. The patient specific contact surface 962 can be non-round in oneembodiment. The patient specific contact surface 962 can be elongated inone embodiment. In some embodiment, the shoulder guide 950 is configuredto eliminate or compensate for there being no glenoid rim member 958 ina posterior side of the guide 950. For example, the patient specificcontact surface 962 can be elongated and can extend in a posteriordirection. In some embodiments, the contact surface 962 is elongated anda rim member 958 is disposed in the posterior portion of the guide 950.In other embodiments the contact surface 962 is sufficiently elongatedto eliminate the posterior side rim member 958. The patient specificcontact surface 962 can have an anterior-posterior extent 976 and asuperior-inferior extent 980 in one embodiment. FIG. 26B shows that theanterior-posterior extent 976 can be greater than the superior-inferiorextent 980. In one embodiment, the anterior-posterior extent 976 is morethan 20% larger than the superior-inferior extent 980 of the patientspecific contact surface 962. In one embodiment, the anterior-posteriorextent 976 is more than 30% larger than the superior-inferior extent 980of the patient specific contact surface 962. In one embodiment, theanterior-posterior extent 976 is more than 40% larger than thesuperior-inferior extent 980 of the patient specific contact surface962. In one embodiment, the anterior-posterior extent 976 is more than50% larger than the superior-inferior extent 980 of the patient specificcontact surface 962. In one embodiment, the anterior-posterior extent976 is more than 70% larger than the superior-inferior extent 980 of thepatient specific contact surface 962. In one embodiment, theanterior-posterior extent 976 is more than 80% larger than thesuperior-inferior extent 980 of the patient specific contact surface962. In one embodiment the anterior-posterior extent 976 is between 20and 100% larger than the superior-inferior extent 980 of the patientspecific contact surface 962.

The central member 964 can have a contact profile, e.g., outer peripherythat is not round, as discussed above. The contact profile can be oblongor elongated. The contact profile can comprise two circular profilesthat are partially overlapping such that end portions thereof can becircular and elongated sides thereof can be somewhat concave. Thepatient specific contact surface 968 can be formed to follow a naturalsurface of the articular portion of the glenoid 18, e.g., having agenerally convex profile to follow the generally concave form of thearticular surface.

The greater anterior-posterior extent 976 of the patient specificshoulder guide 950 compensates for the absence of any glenoid rimmembers 958 in the posterior portion 952. The shoulder guide 950 isconfigured to eliminate or compensate for there being no support on theposterior portion 952 of the guide 950. For example, theanterior-posterior extent 976 can be elongated more toward the posteriordirection. In some embodiments, anterior-posterior extent 976 issufficient to exclude the presence of rim contact in the posterior sideof the rim in use. For example, any force directed toward the medial andposterior directions of the glenoid 18 will not tend to tip the patientspecific shoulder guide 950. Rather, such forces will be transferred ina controlled manner to a surface of the glenoid 18, e.g., to thesub-chondral or cartilage surface thereof. By elongating theanterior-posterior extent 976 greater control of the patient specificshoulder guide 950 can be provided without unnecessarily expanding thesuperior-inferior extent 980. The anterior-posterior extent 976 need notbe centered on the central channel 984. Rather, the anterior-posteriorextent 976 can extend a greater amount toward the posterior directionthan toward the anterior direction. This can further help compensate forthe lack of glenoid rim members 958 in the posterior portion 952 of thepatient specific shoulder guide 950.

A modified embodiment of the patient specific shoulder guide 950includes a side member similar to the side member 926 in the patientspecific shoulder guide 900. Such a side member can have a side channeldisposed therethrough similar to the side channel 928 of the patientspecific shoulder guide 900.

The patient specific shoulder guide 950 can have a span 930 with any ofthe amounts or degrees discussed above in connection with patientspecific shoulder guide 900. The span 930 is generally unobstructed ofany glenoid rim members 958. A zone can be provided in which the glenoidrim members 958 are disposed, as discussed above in connection with thepatient specific shoulder guide 900.

Terminology

Although certain embodiments have been described herein, the implantsand methods described herein can interchangeably use any articularcomponent, as the context may dictate.

As used herein, the relative terms “proximal” and “distal” shall bedefined from the perspective of the implant. Thus, proximal refers tothe direction of the articular component and distal refers to thedirection of an anchor component, such as a stem of a humeral anchor ora thread or porous surface or other anchoring structure of a stemlessanchor when the implant is assembled.

Conditional language, such as “can,” “could,” “might,” or “may,” unlessspecifically stated otherwise, or otherwise understood within thecontext as used, is generally intended to convey that certainembodiments include, while other embodiments do not include, certainfeatures, elements, and/or steps. Thus, such conditional language is notgenerally intended to imply that features, elements, and/or steps are inany way required for one or more embodiments.

The terms “comprising,” “including,” “having,” and the like aresynonymous and are used inclusively, in an open-ended fashion, and donot exclude additional elements, features, acts, operations, and soforth. Also, the term “or” is used in its inclusive sense (and not inits exclusive sense) so that when used, for example, to connect a listof elements, the term “or” means one, some, or all of the elements inthe list. In addition, the articles “a,” “an,” and “the” as used in thisapplication and the appended claims are to be construed to mean “one ormore” or “at least one” unless specified otherwise.

The ranges disclosed herein also encompass any and all overlap,sub-ranges, and combinations thereof. Language such as “up to,” “atleast,” “greater than,” “less than,” “between,” and the like includesthe number recited. Numbers preceded by a term such as “about” or“approximately” include the recited numbers and should be interpretedbased on the circumstances (e.g., as accurate as reasonably possibleunder the circumstances, for example ±5%, ±10%, ±15%, etc.). Forexample, “about 1” includes “1.” Phrases preceded by a term such as“substantially,” “generally,” and the like include the recited phraseand should be interpreted based on the circumstances (e.g., as much asreasonably possible under the circumstances). For example,“substantially spherical” includes “spherical.” Unless stated otherwise,all measurements are at standard conditions including temperature andpressure.

As used herein, a phrase referring to “at least one of” a list of itemsrefers to any combination of those items, including single members. Asan example, “at least one of: A, B, or C” is intended to cover: A, B, C,A and B, A and C, B and C, and A, B, and C. Conjunctive language such asthe phrase “at least one of X, Y and Z,” unless specifically statedotherwise, is otherwise understood with the context as used in generalto convey that an item, term, etc. may be at least one of X, Y or Z.Thus, such conjunctive language is not generally intended to imply thatcertain embodiments require at least one of X, at least one of Y and atleast one of Z to each be present.

Although certain embodiments and examples have been described herein, itshould be emphasized that many variations and modifications may be madeto the humeral head assembly shown and described in the presentdisclosure, the elements of which are to be understood as beingdifferently combined and/or modified to form still further embodimentsor acceptable examples. All such modifications and variations areintended to be included herein within the scope of this disclosure. Awide variety of designs and approaches are possible. No feature,structure, or step disclosed herein is essential or indispensable.

Some embodiments have been described in connection with the accompanyingdrawings. However, it should be understood that the figures are notdrawn to scale. Distances, angles, etc. are merely illustrative and donot necessarily bear an exact relationship to actual dimensions andlayout of the devices illustrated. Components can be added, removed,and/or rearranged. Further, the disclosure herein of any particularfeature, aspect, method, property, characteristic, quality, attribute,element, or the like in connection with various embodiments can be usedin all other embodiments set forth herein. Additionally, it will berecognized that any methods described herein may be practiced using anydevice suitable for performing the recited steps.

For purposes of this disclosure, certain aspects, advantages, and novelfeatures are described herein. It is to be understood that notnecessarily all such advantages may be achieved in accordance with anyparticular embodiment. Thus, for example, those skilled in the art willrecognize that the disclosure may be embodied or carried out in a mannerthat achieves one advantage or a group of advantages as taught hereinwithout necessarily achieving other advantages as may be taught orsuggested herein.

Moreover, while illustrative embodiments have been described herein, itwill be understood by those skilled in the art that the scope of theinventions extends beyond the specifically disclosed embodiments to anyand all embodiments having equivalent elements, modifications,omissions, combinations or sub-combinations of the specific features andaspects of the embodiments (e.g., of aspects across variousembodiments), adaptations and/or alterations, and uses of the inventionsas would be appreciated by those in the art based on the presentdisclosure. The limitations in the claims are to be interpreted broadlybased on the language employed in the claims and not limited to theexamples described in the present specification or during theprosecution of the application, which examples are to be construed asnon-exclusive. Further, the actions of the disclosed processes andmethods may be modified in any manner, including by reordering actionsand/or inserting additional actions and/or deleting actions. It isintended, therefore, that the specification and examples be consideredas illustrative only, with a true scope and spirit being indicated bythe claims and their full scope of equivalents.

Any methods disclosed herein need not be performed in the order recited.The methods disclosed herein include certain actions taken by apractitioner; however, they can also include any third-party instructionof those actions, either expressly or by implication. For example,actions such as “coupling a glenoid guide with the glenoid rim” include“instructing coupling of a glenoid guide with a glenoid rim.”

1-50. (canceled)
 51. A patient specific shoulder guide, comprising: acentral member configured to contact a location of a glenoid surfacelocated inward of a glenoid rim of a glenoid; a plurality of peripheralmembers, each peripheral member having a patient specific surfaceconfigured to contact points of the glenoid rim of the glenoid of aspecific patient; wherein the peripheral members and the central memberprovide for stable positioning of the patient specific shoulder guide;and wherein, in use, all of the peripheral members contact an anteriorportion of the glenoid rim.
 52. The patient specific shoulder guide ofclaim 51, the central member comprises a patient specific contactsurface.
 53. The patient specific shoulder guide of claim 51, whereinthe guide consists of only three peripheral members.
 54. The patientspecific shoulder guide of claim 51, wherein the central membercomprises a circular contact profile.
 55. The patient specific shoulderguide of claim 51, wherein the central member comprises an elongatecontact profile.
 56. The patient specific shoulder guide of claim 54,wherein the central member comprises an ellipsoid contact profile. 57.The patient specific shoulder guide of claim 54, wherein a longitudinalaxis of the elongate contact profile extends in an anterior-posteriordirection of the guide.
 58. The patient specific shoulder guide of claim51, wherein the central hub or central member includes a central channelfor implanting a guide pin in a central region of the glenoid.
 59. Thepatient specific shoulder guide of claim 51, further comprising a sidechannel for securing the guide against rotation.
 60. The patientspecific shoulder guide of claim 59, wherein the side channel isdisposed through the central hub or central member.
 61. The patientspecific shoulder guide of claim 51, further comprising a side channelfor securing the guide against rotation. 62.-112. (canceled)